tag:theconversation.com,2011:/ca/topics/sperm-199/articlesSperm – The Conversation2024-03-13T15:03:15Ztag:theconversation.com,2011:article/2255962024-03-13T15:03:15Z2024-03-13T15:03:15ZIt’s a myth that male animals are usually larger than females – new study<p>Males are bigger than females, right? Generally, this is true of humans – imagine the extremes of Dwayne “The Rock” Johnson and singer Kylie Minogue. It is also true of other familiar mammals including pets, such as cats and dogs, and livestock such as sheep and cows.</p>
<p>But <a href="https://www.nature.com/articles/s41467-024-45739-5">a new study</a> by US scientist Kaia Tombak and colleagues found that, in many mammal species, males are not larger than females. In fact, in a comparison of 429 species in the wild, 50% of species including rodents and some bats – which make up <a href="https://news.mongabay.com/2022/04/of-rats-and-bats-hundreds-of-mammal-species-still-unidentified-study-says/">a large proportion</a> of all mammal species – showed no difference in body size between the sexes. Male-biased size dimorphism (where males are larger than females) was found in only 28% of mammal species.</p>
<p>So, why do a lot of people have a misconception that males are normally larger than females? </p>
<p><a href="https://www.nature.com/scitable/students-page/160/">Anisogamy</a> is the term used to describe the difference in sex cells – small, numerous, sperm, compared to relatively large eggs. Males can produce sperm throughout most of their lifespan, whereas females are born with a finite number of eggs. Therefore, females (or rather, their eggs), are a scare resource for which males compete for access. Generally, in species where females are a limited resource that males need to fight over, males are larger than females.</p>
<p>In terms of evolution, most males have been shaped to be larger, bolder, heavier, more adorned and have more weaponry than females. This is due to males fighting to acquire females – a larger stag with bigger antlers would do much better in a fight, <a href="https://www.discoverwildlife.com/animal-%20facts/mammals/understand-the-british-deer-rut">known as a rut</a>, than a small stag with tiny antlers. So, bigger usually wins.</p>
<p>This includes species such as lions and baboons, where size is an advantage when competing physically for mates. Male northern elephant seals, who fight for access to harems of females, show the largest male-biased size dimorphism, being over 3.2 times heavier than females. These are the animals that tend to attract research</p>
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<h2>The strange world of fish</h2>
<p>But, what happens in species where males don’t fight for access to females? Generally, females are larger than males. This is because larger females usually produce more offspring. Indeed, Tombak’s study noted that larger female rabbits usually have multiple litters each mating season. Being a larger female is much more advantageous in terms of reproductive success. But more so when offspring do not need extended parental care and when gestation periods are short.</p>
<p>The most extreme sexual size dimorphism is found outside of mammals. Cichlid fish (<em>Lamprologus callipterus</em>) males are up to 60 times larger than females. The males protect empty snail shells for the females to breed in. <a href="https://link.springer.com/article/10.1007/s12038-010-0030-6">Larger females</a> can produce more offspring but they need larger shells and therefore a larger male to defend those shells.</p>
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<p>In mammals, the largest female-biased size dimorphism is found in peninsular tube-nosed bats, where females are 1.4 times the size of males. However, more dimorphism in body size is seen in fish, reptiles and insects. For example, the female orb-weaving spider (<em>Nephila plumipes</em>) has a much larger body size than the male, reaching up to ten times his size. Size dimorphism also shows a correlation with cannibalism, where larger females are more likely to eat their male partner.</p>
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<a href="https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Large spider and small one in a web" src="https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581306/original/file-20240312-22-e1nldo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A female golden orb weaving spider and the smaller male.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-photograph-female-golden-orb-weaving-1692871246">Cassandra Madsen/Shutterstock</a></span>
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<p>Anglerfish that typically live at the bottom of oceans, are an example of extreme sexual dimorphism in body size. While the females look like typical fish, the males are tiny, basic organisms. In order to survive, the male needs to fuse with a female, tapping into her nutrients to produce enough sperm to fertilise her. Female deep-sea anglerfish (<em>Ceratias
holboelli</em>) are <a href="https://www.livescience.com/49330-animal-sex-anglerfish.html">60 times longer</a> and half a million times heavier than males.</p>
<p>But, the most extreme sexual size dimorphism is found in rhizocephala, types of barnacle where the male looks like a larvae. Once a male finds a mate, he <a href="https://www.wired.com/2015/07/absurd-creature-of-the-week-rhizocephalan/">inserts himself into the females</a>, transforming into nothing more than a mass of cells.</p>
<h2>What about mammals?</h2>
<p>So, why isn’t sexual size dimorphism seen in more mammals? Mammals tend to have fewer offspring than other species such as fish or spiders. They only have a few offspring at a time, and often have long gestation periods or extended periods of parental care. In addition, the majority of mammals are monogamous, so there is less need for males to fight over females. That’s why species such as lemurs, golden moles, horses, zebra and tenrecs, usually have similar sized males and females.</p>
<p>It is thought that biases in the scientific literature may have led to the misconception that males are normally bigger as research historically focused on <a href="https://wwf.panda.org/discover/our_focus/wildlife_practice/flagship_keystone_indicator_definition/">species considered “charismatic”</a>, such as primates and carnivores, that attract funding. These are some of the few mammalian species where males compete for mates, and so gain an evolutionary advantage if they are larger. </p>
<p>There was also a bias of <a href="https://www.nationalgeographic.co.uk/science-and-technology/2019/10/once-most-famous-scientists-were-men-thats-changing">male scientists</a> conducting research. And, although a study in 1977 <a href="https://www.journals.uchicago.edu/doi/epdf/10.1086/283223">by a female scientist</a> found that species with little sexual size dimorphism were frequent in mammals, the research was drowned out by studies on charismatic species with a bias towards large males. Perhaps if there had been more female scientists at the time, we might have had a different preconception about body size in the animal kingdom.</p><img src="https://counter.theconversation.com/content/225596/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Gentle works for Nottingham Trent University. </span></em></p>Does size matter? In the animal kingdom, yes.Louise Gentle, Principal Lecturer in Wildlife Conservation, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225332024-02-14T16:55:57Z2024-02-14T16:55:57ZMen become less fertile with age, but the same isn’t true for all animals – new study<figure><img src="https://images.theconversation.com/files/573049/original/file-20240202-27-wscv4y.jpg?ixlib=rb-1.1.0&rect=0%2C34%2C5833%2C3938&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/colorful-balloons-spermatozoid-shape-on-blue-1100465771">olliulli/Shutterstock</a></span></figcaption></figure><p>We take it for granted that humans find it <a href="https://www.tandfonline.com/doi/full/10.3109/09513590.2010.501889">more difficult to conceive</a> as they grow older. But <a href="https://www.nature.com/articles/s41467-024-44768-4">our recent study</a>, which analysed data from 157 animal species, found that male reproductive ageing seems to be a lot less common in other male animals. </p>
<p>With fertility in men <a href="https://www.bmj.com/content/305/6854/609">declining worldwide</a>, understanding ageing of sperm in other animals could give new insights into our own fertility. </p>
<p>Human fertility declines with age because sperm and eggs of older people are <a href="https://academic.oup.com/humupd/article/11/3/261/759255">more deteriorated</a> or fewer in number than those of young people. Reproducing at an older age not only affects your fertility, but can also <a href="https://www.nature.com/articles/nrurol.2013.18">reduce the fertility</a>, survival rate and physical and cognitive performance of the children you conceive.</p>
<h2>Humans versus other animals</h2>
<p>Humans <a href="https://link.springer.com/article/10.1007/s00239-019-09896-2">live considerably longer</a> than we did just a century ago. This <a href="https://www.pnas.org/doi/full/10.1073/pnas.0909606106">recent, rapid extension</a> in our longevity might be one reason why humans reproductively age at faster rates than other animals. Our reproductive ageing rate hasn’t slowed down yet to match our longer lifespans. </p>
<p>Animals might also face greater evolutionary pressure to maximise their reproductive potential at all ages, because most animals reproduce throughout their lives. But this isn’t the case for humans. We rarely <a href="https://academic.oup.com/humrep/article/29/6/1304/625687">reproduce</a> in our late life. </p>
<p>Additionally, we have <a href="https://academic.oup.com/humrep/article/37/4/629/6515525">fewer offspring</a> compared to our ancestors. This makes it harder for natural selection to select genes that improve human reproduction due to less variation in the population’s fecundity. </p>
<h2>Females versus males</h2>
<p>Males and females in many species age reproductively at different rates. </p>
<p>For instance, in red wolves, male reproductive success declines with age but it <a href="https://link.springer.com/article/10.1007/s00265-016-2241-9">does not</a> for females. Yet female killifish show stronger decline in fertility with age <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2656.13382">than males</a>. Despite the fact human females live longer than males, they tend to become infertile <a href="https://www.science.org/doi/abs/10.1126/science.3755843">earlier than men</a>, and go through menopause. </p>
<p>In some species, including humans, where females help raise their grand-offspring (such as humans and whales), females live <a href="https://www.sciencedirect.com/science/article/pii/S0960982218316828?via%3Dihub">much beyond the age</a> of reproduction. An <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsos.191972">evolutionary explanation</a> for this is that older females can better pass on their genes by helping their relatives survive and rear young than by reproducing themselves.</p>
<p>There are some hypotheses that try to explain these <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/acel.13542">sex-specific differences</a> in reproductive ageing. </p>
<p>Sperm are continuously produced in males, but eggs in many species, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8769179/">including humans</a>, are produced early in the life of females. This might lead eggs to <a href="https://academic.oup.com/humupd/article/6/6/532/616993">accumulate more damage</a> due to being stored for longer durations inside older females than sperm are stored in old males. </p>
<p>Another hypothesis suggests that males might age faster because sperm DNA <a href="https://elifesciences.org/articles/80008">accumulate more</a> mutations than egg DNA. Sperm have poorer DNA repair machinery than eggs, causing males to <a href="https://www.nature.com/articles/s41586-023-05752-y">pass on more mutations</a> to the next generation than females with advancing age, a pattern observed across vertebrate animals.</p>
<p>Sexes also face different environmental pressures. For instance, in many mammals, males, <a href="https://theconversation.com/of-mice-and-matriarchs-the-female-led-societies-of-the-animal-kingdom-186875">but not females</a>, disperse away from the family group when they mature. This sort of environmental pressure leads to differences in the strategies males and females use to pass on their genes, which can create differences in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/acel.13542">rates of reproductive ageing</a> between the sexes. </p>
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<img alt="Humpback whale mother with her calf" src="https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Female whales live long after their reproductive window.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/humpback-whale-mother-calf-on-tonga-1907017690">Tomas Kotouc/Shutterstock</a></span>
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<h2>Patterns of reproductive ageing in animals</h2>
<p>In our study, we showed that reproductive ageing rates in males <a href="https://www.nature.com/articles/s41467-024-44768-4">vary vastly</a> across the animal kingdom. We found invertebrates such as crustacea and insects have some of the slowest rates of reproductive ageing, compared to lab rodents who had some of the fastest rates.
Generally though, male animals showed few signs of age-related declines in their ejaculate traits (such as sperm quality and quantity). </p>
<p>We also found that different ejaculate traits, such as sperm viability, number, motility or velocity, aged at different rates.</p>
<p>In species that grow throughout their lives, such as some fish and crustacea, old animals have a lower mortality risk and larger gonads than young males. This can cause old males <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2021.2146">in such species</a> to age at slower rates, with older males producing larger ejaculates than younger males.</p>
<p>In animals such as lab rodents, who have some genetic lines selected for accelerated ageing, reproductive ageing was universal across ejaculate traits. Lab rodents are generally kept in highly controlled environments where ageing is easier to detect – due to fewer confounding effects that could mask ageing. This suggests that a lot of the variation in male reproductive ageing between different species could be due to their environment. </p>
<p>We also discovered that closely related species showed similar rates of decline in ejaculates with age, suggested that ageing is also shaped by an animal’s evolutionary history. </p>
<p>Some of the patterns we mention above also reflected methodological differences between studies. For example, when studies kept male animals as virgins, old males can <a href="https://www.pnas.org/doi/full/10.1073/pnas.2009053117">accumulate more sperm</a> than young males, leading to old males producing larger ejaculates. </p>
<p>Additionally, studies that only sampled young to middle-aged males showed an increase in sperm quality and quantity with age, compared to studies that sampled middle-aged to old males, suggesting that fertility peaks around middle age in male animals generally.</p>
<h2>Reproductive ageing</h2>
<p>Reproductive ageing occurs because as individuals grow older, their sperm and eggs <a href="https://www.nature.com/articles/nrurol.2013.18">accumulate damage</a>. Organisms have evolved to reproduce earlier in life rather than when old, which leads to a <a href="https://academic.oup.com/genetics/article/156/3/927/6051413">weaker ability of natural selection</a> to weed out bad genes that are expressed in old but not young organisms, in turn promoting ageing.</p>
<p>There are however, opposing forces that determine whether old individuals will leave more copies of their genes to successive lineages compared to young animals, and reproductive ageing is only one process determining this. </p>
<p><a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/bies.201100157">An alternative hypothesis</a> is that parents who conceive at an older age would have more gene variants for longer lifespans which could benefit their offspring. This could lead to longer lived offspring from older conceiving parents. However evidence for this hypothesis is still limited. </p>
<p>While most scientists accept that at least some reproductive traits decline with age, biologists are still uncovering what the exact mechanisms and evolutionary reasons for these declines are. But by looking at other species to investigate the drivers of reproductive ageing, we can understand and perhaps even seek to alleviate our own reproductive decline with age.</p><img src="https://counter.theconversation.com/content/222533/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Krish Sanghvi receives funding from Society for the study of evolution (Rosemary grant award).</span></em></p><p class="fine-print"><em><span>Irem Sepil receives funding from the Royal Society, BBSRC and Wellcome Trust. </span></em></p><p class="fine-print"><em><span>Regina Vega-Trejo receives funding from Biotechnology and Biological Sciences Research Council.</span></em></p>Understanding how the ageing of sperm works in other animals is more important than ever as human male fertility is in decline.Krish Sanghvi, PhD student at the department of Biology, University of Oxford, University of OxfordIrem Sepil, Lecturer in Evolutionary Biology, University of OxfordRegina Vega-Trejo, Postdoctoral Research Assistant in Evolutionary Biology, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2190052023-12-14T19:19:48Z2023-12-14T19:19:48ZEggs from men, sperm from women: how stem cell science may change how we reproduce<figure><img src="https://images.theconversation.com/files/564442/original/file-20231208-17-22yb4u.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1000%2C748&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/morula-early-stage-embryo-consisting-cells-776035219">nobeastsofierce/Shutterstock</a></span></figcaption></figure><p>It may soon be possible to coax human skin cells into becoming functional eggs and sperm using a technique known as “in vitro gametogenesis”. This involves the creation (genesis) of eggs and sperm (gametes) outside the human body (in vitro). </p>
<p>In theory, a skin cell from a man could be turned into an egg and a skin cell from a woman can become a sperm. Then there’s the possibility of a child having multiple genetically-related parents, or only one.</p>
<p>Some scientists believe human applications of in vitro gametogenesis are a <a href="https://www.statnews.com/2023/10/02/ivg-ivf-replacement-reproductive-technology-hype/">long way off</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1708819232077533218"}"></div></p>
<p>However, scientists who work on human stem cells are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10579208/">actively working</a> on overcoming the barriers. <a href="https://www.statnews.com/2023/04/08/ivf-eggs-hormones-gameto-reproductive-fertilo/">New</a> <a href="https://www.technologyreview.com/2021/10/28/1038172/conception-eggs-reproduction-vitro-gametogenesis/">biotechnology</a> <a href="https://www.newyorker.com/magazine/2023/04/24/the-future-of-fertility">start-ups</a> are also seeking to commercialise this technology.</p>
<p>Here’s what we know about the prospect of human in vitro gametogenesis and why we need to start talking about this now.</p>
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Read more:
<a href="https://theconversation.com/explainer-what-are-stem-cells-14391">Explainer: what are stem cells?</a>
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<h2>Is the technology available?</h2>
<p>In vitro gametogenesis begins with “pluripotent stem cells”, a kind of cell that can develop into many different cell types. The aim is to persuade these stem cells to become eggs or sperm.</p>
<p>These techniques could use stem cells taken from early embryos. But scientists have also worked out how to <a href="https://www.eurostemcell.org/stemcellshorts-what-are-induced-pluripotent-stem-cells">revert adult cells</a> to a pluripotent state. This opens up the possibility of creating eggs or sperm that “belong to” an existing human adult.</p>
<p>Animal studies have been promising. In <a href="https://www.nature.com/articles/490146b">2012</a>, scientists created live-born baby mice using eggs that began their life as skin cells on a mouse tail.</p>
<p>More recently, the technique has been used to facilitate same-sex reproduction. Earlier this year, scientists created mouse pups with <a href="https://www.nature.com/articles/d41586-023-00717-7">two genetic fathers</a> after transforming skin cells from male mice into eggs. Mouse pups with <a href="https://www.nature.com/articles/d41586-018-06999-6">two genetic mothers</a> have also been created.</p>
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<figcaption><span class="caption">How scientists bred mice with two fathers.</span></figcaption>
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<p>Scientists have not yet managed to adapt these techniques to create human gametes. Perhaps because the technology is still in its infancy, Australia’s legal and regulatory systems do not address whether and how the technology should be used. </p>
<p>For example, the National Health and Medical Research Council’s <a href="https://www.nhmrc.gov.au/about-us/publications/art">assisted reproduction guidelines</a>, which were updated in 2023, do not include specific guidance for in vitro-derived gametes. These guidelines will need to be updated if in vitro gametogenesis becomes viable in humans.</p>
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<p>
<em>
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Read more:
<a href="https://theconversation.com/the-future-of-stem-cells-tackling-hype-versus-hope-72052">The future of stem cells: tackling hype versus hope</a>
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<h2>The potential</h2>
<p>There are three distinct clinical applications of this technology.</p>
<p>First, in vitro gametogenesis could streamline IVF. Egg retrieval currently involves repeated hormone injections, a minor surgical procedure, and the <a href="https://www.mayoclinic.org/diseases-conditions/ovarian-hyperstimulation-syndrome-ohss/symptoms-causes/syc-20354697">risk</a> of overstimulating the ovaries. In vitro gametogenesis could eliminate these problems.</p>
<p>Second, the technology could circumvent some forms of medical infertility. For example, it could be used to generate eggs for women born without functioning ovaries or following early menopause.</p>
<p>Third, the technology could allow same-sex couples to have children who are genetically related to both parents.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/promising-assisted-reproductive-technologies-come-with-ethical-legal-and-social-challenges-a-developmental-biologist-and-a-bioethicist-discuss-ivf-abortion-and-the-mice-with-two-dads-208276">Promising assisted reproductive technologies come with ethical, legal and social challenges – a developmental biologist and a bioethicist discuss IVF, abortion and the mice with two dads</a>
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<h2>Legal, regulatory and ethical issues</h2>
<p>If the technology becomes viable, in vitro gametogenesis will alter the dynamics of how we create families in unprecedented ways. How we should respond requires careful consideration.</p>
<p><strong>1. Is it safe?</strong></p>
<p>Careful trials, rigorous monitoring, and follow-up of any children born will be essential – as it has been for other <a href="https://theconversation.com/maeves-law-would-let-ivf-parents-access-technology-to-prevent-mitochondrial-disease-heres-what-the-senate-is-debating-176668">reproductive</a> <a href="https://theconversation.com/rest-assured-ivf-babies-grow-into-healthy-adults-23432">technologies</a>, including IVF.</p>
<p><strong>2. Is it equitable?</strong></p>
<p>Other issues relate to access. It might seem unjust if the technology is only available to the wealthy. Public funding could help – but whether this is appropriate depends on whether the state <a href="https://theconversation.com/ideas-for-australia-rethinking-funding-and-priorities-in-ivf-should-the-state-pay-for-people-to-have-babies-57036">ought to support</a> people’s reproductive projects.</p>
<p><strong>3. Should we restrict access?</strong></p>
<p>For instance, pregnancy is rare in older women, largely because egg count and quality <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/age-and-fertility">decline with age</a>. In vitro gametogenesis would theoretically provide “fresh” eggs for women of any age. But helping older women become parents is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5566409/">controversial</a>, due to physical, psychological and other factors associated with having babies later in life.</p>
<p><strong>4. We’d still need surrogates</strong></p>
<p>If we took skin cells from each male partner and created an embryo, that embryo would still need a surrogate to carry the pregnancy. Unfortunately, Australia has a shortfall of surrogates. International surrogacy provides an alternative, but carries <a href="https://theconversation.com/its-hard-to-find-a-surrogate-in-australia-but-heading-overseas-comes-with-risks-206182">legal, ethical and practical difficulties</a>. Unless access to surrogacy is improved domestically, benefits to male couples will be limited. </p>
<p><strong>5. Who are the legal parents?</strong></p>
<p>In vitro gametogenesis also raises questions about who are the future child’s legal parents. We already see related legal debates surrounding non-traditional families formed through surrogacy, egg donation and sperm donation. </p>
<p>In vitro gametogenesis could theoretically also be used to create children with more than two genetic parents, or with only one. These possibilities likewise require us to update our current understandings of parenthood.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-may-one-day-grow-babies-outside-the-womb-but-there-are-many-things-to-consider-first-125709">We may one day grow babies outside the womb, but there are many things to consider first</a>
</strong>
</em>
</p>
<hr>
<h2>How far is too far?</h2>
<p>Of the potential uses already mentioned, same-sex reproduction is the most controversial. The reproductive limitations imposed by being in a same-sex relationship are sometimes seen as a “social” form of infertility the medical profession is not obligated to fix.</p>
<p>The moral stakes, however, are virtually identical regardless of whether in vitro gametogenesis is used by same-sex or opposite-sex couples. Both uses of the technology fulfil exactly the same goal: helping couples fulfil their desire to have a child genetically related to both parents. It would be unjust to deny access to only one of these groups.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Same-sex female couple cooking in kitchen, one feeding the other fruit" src="https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564457/original/file-20231208-21-83z5z9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Who should have access to this technology? How about same-sex couples?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lesbian-couple-cooking-kitchen-together-1071305168">Rawpixel.com/Shutterstock</a></span>
</figcaption>
</figure>
<p>But same-sex reproduction is only the tip of the iceberg. In vitro gametogenesis could theoretically facilitate “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6973109/">solo reproduction</a>” by deriving both eggs and sperm from the same individual. Interestingly, a child created this way would not be a clone of its parent, since the process of gamete formation would shuffle the parent’s genetic material and create a genetically distinct individual.</p>
<p>Or people could engage in “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4215291/">multiplex parenting</a>” combining genetic material from more than two individuals. Imagine, for example, that two couples create embryos via IVF. In vitro gametogenesis could then be used to derive eggs and sperm from each of these two separate embryos, which could subsequently be used to conceive a single child that is genetically related to all four adults.</p>
<p>Finally, in vitro gametogenesis could revolutionise prenatal genetic selection. We’d have <a href="https://rmanetwork.com/blog/number-of-eggs-good-ivf-in-vitro-fertilization/">many more embryos</a> than available during regular IVF to screen for genetic diseases and traits.</p>
<p>So it would be urgent to discuss “designer babies”, eugenics, and whether we have a <a href="https://bioedge.org/bioethics-d75/savulescu-interviewed-on-procreative-beneficence/">moral obligation</a> to conceive children with the best chance of a good life.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/worlds-first-synthetic-embryo-why-this-research-is-more-important-than-you-think-188217">World's first 'synthetic embryo': why this research is more important than you think</a>
</strong>
</em>
</p>
<hr>
<h2>We need to start talking about this now</h2>
<p>Both law and ethics can lag behind new technologies, particularly when their implications are as profound and far-reaching as the implications of in vitro gametogenesis.</p>
<p>We need to discuss how this technology should be regulated before it is rolled out. Given how rapidly the science is developing, we should begin this discussion now. </p>
<hr>
<p><em>Laura Smith, a masters student from Monash University, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/219005/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julian Koplin receives research funding from Ferring Pharmaceuticals for an unrelated project.</span></em></p><p class="fine-print"><em><span>Neera Bhatia receives funding from UKRI Arts and Humanities Research Council for an unrelated project.</span></em></p>The technology may be here sooner than we think. But we have so much to discuss first.Julian Koplin, Lecturer in Bioethics, Monash University & Honorary fellow, Melbourne Law School, Monash UniversityNeera Bhatia, Associate Professor in Law, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2177872023-12-11T01:07:04Z2023-12-11T01:07:04ZMale infertility is more common than you may think. Here are 5 ways to protect your sperm<figure><img src="https://images.theconversation.com/files/562602/original/file-20231130-15-oj3ctt.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C5126%2C3592&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Infertility is often thought of as a female problem but <a href="https://theconversation.com/problems-conceiving-are-not-just-about-women-male-infertility-is-behind-1-in-3-ivf-cycles-192183">one in three IVF cycles</a> in Australia involve male infertility.</p>
<p>We recently published a <a href="https://pubmed.ncbi.nlm.nih.gov/37695221/">review of the literature</a> on whether men diagnosed with male factor infertility experience greater psychological distress than fertile men or men with an infertile partner. We found irrespective of the cause of infertility, men in couples with infertility have more symptoms of depression, anxiety and general psychological distress, worse quality of some aspects of life, and lower self-esteem than fertile men. </p>
<p>Research also shows sperm counts are <a href="https://doi.org/10.1093/humupd/dmac035">declining worldwide</a>, and that lifestyle and environmental factors can reduce male fertility.</p>
<p>While most <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7008178/">male causes of infertility</a> are not preventable, it’s important to know how to keep your sperm as healthy as possible. Here are five things men can do to boost their fertility. </p>
<h2>1. Try to be in the healthy weight range</h2>
<p>Obesity <a href="https://doi.org/10.1016/j.fertnstert.2023.10.017">causes hormonal changes</a> that have <a href="https://pubmed.ncbi.nlm.nih.gov/32399992/">negative effects on semen</a>, including the total number of sperm, the ability of the sperm to move, the number of live sperm, and the number of sperm with a normal shape. </p>
<p>These reduce the chance of both <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/andr.13552">spontaneous and IVF conception</a>.</p>
<p>The good news is the adverse effects on fertility caused by excess weight in men are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408383/">reversible</a>. Regular <a href="https://doi.org/10.1016/j.fertnstert.2023.10.017">exercise</a> and a healthy diet can help reduce weight and improve sperm quality. </p>
<p>There is strong evidence a healthy diet rich in fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, and low in red and processed meats, sweets, and sweetened beverages is linked to <a href="https://doi.org/10.1016/j.fertnstert.2023.10.013">better sperm quality</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/problems-conceiving-are-not-just-about-women-male-infertility-is-behind-1-in-3-ivf-cycles-192183">Problems conceiving are not just about women. Male infertility is behind 1 in 3 IVF cycles</a>
</strong>
</em>
</p>
<hr>
<h2>2. Avoid recreational drugs</h2>
<p>Recreational drug use is associated with poorer reproductive health. Psychoactive drugs such as cocaine, benzodiazepines, heroin, methamphetamine, oxycodone and ecstasy <a href="https://rbej.biomedcentral.com/articles/10.1186/s12958-023-01098-2">negatively affect male reproductive functions</a> including sexual urge, testosterone production, sperm production and sperm quality. </p>
<p>While research on the link between <a href="https://doi.org/10.1111/andr.12585">marijuana use and sperm quality</a> is inconclusive, some evidence suggests frequent marijuana use can reduce sperm quality and is a risk factor for testicular cancer. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man's hand holding up bag of white powder" src="https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562606/original/file-20231130-23-6t0is.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Recreational drug use is associated with poorer reproductive health.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>3. Stay clear of anabolic steroids</h2>
<p>Some men use anabolic steroids to enhance their physical performance and appearance. Globally, it’s estimated about <a href="https://doi.org/10.1016/j.fertnstert.2023.09.016">one in 16 men</a> (6.4%) use anabolic steroids sometime during their life. Male weightlifters aged 20-39 years, fighters, and security personnel are among the most <a href="https://www.fertstert.org/article/S0015-0282(23)01882-4/pdf">common users of anabolic steroids</a>.</p>
<p>Anabolic steroids contribute to muscle growth and fat loss, but they also affect sexual function, including by reducing the <a href="https://www.fertstert.org/article/S0015-0282(23)01882-4/pdf">size of testicles</a>, reducing or stopping <a href="https://www.fertstert.org/article/S0015-0282(23)01882-4/pdf">sperm production</a>, and causing <a href="https://www.fertstert.org/article/S0015-0282(23)01882-4/pdf">impotence and infertility</a>.</p>
<p>Studies show most <a href="https://doi.org/10.1111/jsm.12890">men start producing sperm again</a> within a year of stopping anabolic steroids. But a <a href="https://doi.org/10.1016/j.fertnstert.2023.09.016">recent study</a> of men who became infertile as a result of anabolic steroids found that for some there is long-term damage to sperm production. </p>
<p>In this study of men who had stopped using anabolic steroids and had a six-month course of hormone treatment to improve sperm production, more than half still produced no sperm at all or very few sperm after six months. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/science-or-snake-oil-do-men-need-sperm-health-supplements-84379">Science or Snake Oil: do men need sperm health supplements?</a>
</strong>
</em>
</p>
<hr>
<h2>4. Quit smoking and vaping</h2>
<p>We all know tobacco smoking is terrible for our general health but there is now evidence it’s also bad for <a href="https://pubmed.ncbi.nlm.nih.gov/37628668/">male fertility</a> and <a href="https://doi.org/10.1080%2F00325481.2015.1015928">reproductive outcomes</a>.</p>
<p>In the past decade, vaping has become increasingly popular, especially among young adults. More than 500 e-cigarette brands and 8,000 flavours have been <a href="https://www.mdpi.com/2075-1729/13/3/827">commercialised</a>. There is now growing evidence from animal studies that vaping can <a href="https://doi.org/10.3390/life13030827">harm male reproductive health</a> and experts recommend avoiding vaping when <a href="https://www.mdpi.com/2075-1729/13/3/827">trying to conceive</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man blowing out vape vapour" src="https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562609/original/file-20231130-29-subdcw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">We know smoking harms reproductive health, and there’s increasing evidence vaping does too.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>5. Reduce exposure to environmental chemicals</h2>
<p>In our everyday lives we are exposed to many different environmental chemicals – through the products we use, the food we eat, and the air we breathe. So-called <a href="https://doi.org/10.1016/j.fertnstert.2023.10.008">endocrine-disrupting chemicals</a> can reduce the quality of sperm and cause problems with fertility because they can mimic or block male sex hormones. </p>
<p>It’s impossible to avoid these chemicals completely, because they are all around us. But you can take some simple steps to <a href="https://www.yourfertility.org.au/everyone/drugs-chemicals/chemicals-our-environment">reduce your exposure</a>, including:</p>
<ul>
<li><p>washing fruit and vegetables</p></li>
<li><p>eating fewer processed, canned or pre-packaged foods</p></li>
<li><p>drinking from glass or hard plastic bottles, rather than soft plastic bottles</p></li>
<li><p>heating food in a china or glass bowl covered with paper towel or a plate rather than using plastic takeaway containers or those covered with cling wrap. </p></li>
</ul>
<p>To inform men about how to look after their sperm, <a href="https://www.yourfertility.org.au/">Your Fertility</a>, a fertility health promotion program delivered by the Victorian Assisted Reproductive Treatment Authority, teamed up with Melbourne comedian Michael Shafar to create some helpful <a href="https://www.yourfertility.org.au/fertility-week-2022">educational videos</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/considering-using-ivf-to-have-a-baby-heres-what-you-need-to-know-108910">Considering using IVF to have a baby? Here's what you need to know</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/217787/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karin Hammarberg works for the Victorian Assisted Reproductive Treatment Authority which manages the Your Fertility program. </span></em></p>With sperm counts declining world wide, it’s important to know how to keep your sperm as healthy as possible.Karin Hammarberg, Senior Research Fellow, Global and Women's Health, School of Public Health & Preventive Medicine, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2077562023-07-18T14:32:17Z2023-07-18T14:32:17ZMale fertility crisis: what environmental contaminants have got to do with it<figure><img src="https://images.theconversation.com/files/537480/original/file-20230714-17-hkfcq9.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7487%2C4976&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are multiple causes of male infertility.</span> <span class="attribution"><span class="source">Jacob Lund/Shutterstock</span></span></figcaption></figure><p>The World Health Organisation (WHO) <a href="https://www.who.int/news-room/fact-sheets/detail/infertility">recently reported</a> that around one in six couples globally are affected by infertility. For many years people tended to blame women for a couple’s infertility – especially in <a href="https://academic.oup.com/humrep/article/27/5/1383/696393">African countries</a>. </p>
<p>But it’s now known that male factor infertility contributes about 50% of total cases. And men worldwide – <a href="https://www.ajol.info/index.php/ahs/article/view/158723">Africa included</a> – are experiencing a <a href="https://rbej.biomedcentral.com/articles/10.1186/s12958-023-01054-0">worrying trend</a> of decreased sperm count and quality. </p>
<p>There are multiple causes of male infertility. However, it is clear that <a href="https://www.tandfonline.com/doi/full/10.1016/j.aju.2017.12.004">environmental contaminants</a> play a large part in declining fertility worldwide. Concern is rising about substances such as per- and polyfluoroalkyl substances, nanomaterials and endocrine disrupting compounds. These substances are found everywhere in modern <a href="https://portal.ct.gov/DEEP/Remediation--Site-Clean-Up/Contaminants-of-Emerging-Concern/Contaminants-of-Emerging-Concern#:%7E:text=According%20to%20EPA%2C%20an%20emerging,a%20new%20pathway%20to%20humans.">everyday lives</a>. Most are present in personal-care products such as soaps, shampoos and hair sprays, as well as food wrap, water bottles and many other items. </p>
<p>Other contaminants that are <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969721036974?via%3Dihub">increasing</a> in prevalence and show signs of entering our food chain are pesticides and medication. Recent <a href="https://www.mdpi.com/2305-6304/11/4/330">research</a> in our laboratory found high traces of these in the nearshore marine environment of False Bay, as well as in rivers and air in agricultural areas of South Africa’s Western Cape province. </p>
<p>Our study suggests that these “contaminants of emerging concern” might be contributing to the male infertility crisis in surprising ways.</p>
<p>In our study, we described the effects of contaminants such as pharmaceuticals and pesticides on male reproduction. We propose that these can affect men’s reproductive fitness either by interacting with their brain, or by targeting the reproductive organs such as the testes directly.</p>
<p>The public needs to be aware of the effects of contaminants in the environment on reproductive health. Our research could assist in finding a possible cause of unexplained infertility. It may also lead to preventive treatments. </p>
<h2>Impact on male fertility</h2>
<p>Our research suggests that across animals, including humans, most contaminants of emerging concern interfere with hormone function. They target the hypothalamic-pituitary-gonadal axis. </p>
<p>The axis is the part of the <a href="https://www.epa.gov/endocrine-disruption/overview-endocrine-system#:%7E:text=The%20endocrine%20system%2C%20made%20up,the%20metabolism%20and%20blood%20sugar">endocrine system</a> that controls reproductive functions – the ability to produce sperm in men and eggs in women. When the axis is disrupted, reproductive hormones aren’t released as normal. This influences the rate and quality of sperm production.</p>
<p>We report that contaminants of emerging concern can also act directly on testicles by disrupting the blood-testis barrier. This physical barrier protects the developing sperm from harmful substances that may be present in the bloodstream. Once contaminants cross the barrier, these compounds move into the compartments of the testis where sperm are produced and can interact with the cells that are involved in sperm production. These cells also play important roles in regulating the production of hormones such as testosterone. Contaminants can either directly damage these cells or interfere with their function.</p>
<p>The contaminants can also directly damage the DNA in the sperm cells, leading to genetic changes that can affect the quality of the sperm and their ability to fertilise an egg. This can result in infertility or compromise the health of the resulting children.</p>
<h2>The legacy of fathers</h2>
<p>The way environmental factors affect fertility and cause effects over multiple generations may involve the <a href="https://pubmed.ncbi.nlm.nih.gov/23955672/#:%7E:text=The%20sperm%20epigenome%20is%20unique,be%20compacted%20and%20highly%20organized.">epigenome of sperm</a>. The mechanisms are far from being fully understood. But these epigenetic marks can affect how the genes within sperm work without changing the underlying <a href="https://www.mdpi.com/1422-0067/23/6/3350">DNA sequence</a>. </p>
<p>Yet, these changes can be passed down from a parent to their child. This can happen in two ways: when the germ cells that make sperm are exposed to contaminants of emerging concern, and when the sperm itself is affected. In both cases, epigenetic changes can be passed on to future generations who have not been directly exposed to the contaminants. </p>
<p>One category of compounds whose <a href="https://www.tandfonline.com/doi/full/10.1080/15287394.2020.1786483">impact</a> on epigenetic marks that has been <a href="https://onlinelibrary.wiley.com/doi/10.1002/tox.22819">extensively</a> <a href="https://clinicalepigeneticsjournal.biomedcentral.com/articles/10.1186/s13148-017-0376-9">studied</a> is nonsteroidal anti-inflammatory drugs such as paracetamol and ibuprofen. These drugs are used for managing pain and inflammation. </p>
<p>But our research suggests that they also have adverse effects on reproductive health in children. For example, exposure to these pharmaceuticals during pregnancy can lead to reduction in testosterone levels and changes in genes involved in neurodevelopment in boys. Further <a href="https://www.frontiersin.org/articles/10.3389/fgene.2022.929471/full">studies</a> have also <a href="https://academic.oup.com/eep/article/5/2/dvz008/5499083">suggested</a> that when adults were exposed to insecticides their sperm carried marks in genes involved in neurological functions including susceptibility to autism spectrum disorders, schizophrenia and bipolar disorder. </p>
<p>These effects may be particularly significant when exposure to contaminants of emerging concern is cumulative. And that’s often the case. These contaminants can accumulate in the environment and enter our bodies in various ways, through diet, drinking water, and exposure at work or in recreation. </p>
<p>But there might be solutions to limit their exposure.</p>
<h2>Taking charge</h2>
<p>The numerous pathways in which contaminants of emerging concern contaminate soil, water and air are apparent. But it’s not easy to detect and eradicate these contaminants. So how do we reduce our exposure to them?</p>
<p>Current control measures include regulatory frameworks to limit the use of certain <a href="https://www.foodfocus.co.za/home//Legislation/Food-Safety/AMENDMENT-TO-REGULATIONS-GOVERNING-THE-MAXIMUM-LIMITS-FOR-PESTICIDE-RESIDUES">pesticides</a> <a href="https://www.who.int/publications/i/item/9789240014770">or</a> <a href="https://www.oncotarget.com/article/12956/text/">pharmaceuticals</a>, and develop safer alternatives. There are personal protective measures to take, such as using air and water filters, and reducing the use of plastic products that may contain contaminants of emerging concern.</p>
<p>Public health campaigns could raise awareness about the risks of exposure, or the development of new technologies that can detect and quantify these contaminants in the environment more accurately.</p>
<p>Individuals, especially men, should be made aware of the rise in male infertility and how improving their own health and avoiding exposure to contaminants can increase their chances of fatherhood.</p><img src="https://counter.theconversation.com/content/207756/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>For many years women were blamed for a couple’s infertility. But it’s now known that male factor infertility contributes to about 50% of total cases.Daniel Marcu, PhD Researcher in Reproduction and Genetics, University of East AngliaLiana Maree, Senior Lecturer, University of the Western CapeShannen Keyser, Lecturer, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2028542023-05-31T01:58:39Z2023-05-31T01:58:39ZTrying for a baby? What you need to know about a vital part of your womb (and how to look after it)<figure><img src="https://images.theconversation.com/files/525306/original/file-20230510-19-vyabvw.jpg?ixlib=rb-1.1.0&rect=50%2C101%2C4128%2C2720&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-photo-young-woman-picking-sanitary-528070513">Shutterstock</a></span></figcaption></figure><p>Human reproduction is completely dependent on the healthy function of an underestimated but vital organ: the endometrium. This is the spongy tissue that lines the inner surface of the womb.</p>
<p>In the first half of the menstrual cycle, a healthy endometrium expands in response to the estrogen produced by a growing egg. The endometrium is then shed each month during menstruation. </p>
<p>Or, in the case of pregnancy, the endometrium accepts and nurtures the embryo.</p>
<h2>So you’re trying to get pregnant. What happens?</h2>
<p>When ovulation is triggered, the ovary starts to produce the hormones estrogen and progesterone. Progesterone causes the endometrial cells to prepare to accept an embryo, in a unique transition called “decidualisation”.</p>
<p>During decidualisation, endometrial cells display proteins that indicate it’s receptive for embryo attachment. After attachment, the junctions between endometrial cells loosen so an embryo can move beneath the endometrial surface. </p>
<p>Endometrial cells secrete substances that nurture the embryo, while immune cells protect the embryo and the endometrium while they move together and the placenta develops. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-to-get-pregnant-30529">Health Check: how to get pregnant</a>
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</em>
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<p>The surface of the endometrium is covered by a shield of glycoproteins (proteins attached to sugars) which protects it from bacteria and viruses. This shield can also <a href="https://doi.org/10.1038/s41598-021-03425-2">prevent an embryo from attaching to the lining</a>.</p>
<p>Progesterone helps to remove this glycoprotein shield about five days after ovulation. This is carefully timed so a fertilised egg will have developed into a blastocyst-stage embryo and be starting to hatch from its shell ready to interact with the exposed endometrial cells.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=441&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=441&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=441&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=554&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=554&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525307/original/file-20230510-19-t3k1xt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=554&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The stages of embryo development.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com">Shutterstock</a></span>
</figcaption>
</figure>
<h2>It prevents the body rejecting the father’s sperm</h2>
<p>The endometrium must also retrain its immune cells to accept an embryo that contains the father’s foreign biological material, or “antigens”. </p>
<p>Tissues bearing these foreign antigens would usually provoke an immune rejection response, but the endometrium has adapted its immune response so an embryo can be accepted, and implant and grow, without rejection. </p>
<p>Although not essential for pregnancy, prior contact with the father’s semen <a href="https://www.jci.org/articles/view/122182">primes the mother’s immune response</a> and promotes acceptance of an embryo. Sexual activity enables paternal antigens, which are present in the fluid around sperm, to interact with the mother’s immune cells in the cervix and endometrium. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whats-the-point-of-sex-its-communication-at-a-biological-level-67847">What's the point of sex? It's communication at a biological level</a>
</strong>
</em>
</p>
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<p>Paternal antigens are taken to lymph glands in the pelvic cavity where they are processed in a way that encourages the mother’s immune response to tolerate – not reject – these paternal antigens. </p>
<p>When paternal antigens on the embryo are next seen by the mother’s endometrial immune cells, they accept the embryo and nurture it. Implantation and placental development can then occur, maximising the chance of progression to a healthy pregnancy.</p>
<h2>Then what happens?</h2>
<p>For an embryo to grow beyond being a blastocyst, it must secure access to a robust blood supply. Oxygen and nutrients are sourced from the mother’s endometrium (called decidua in early pregnancy) during implantation via the placenta which is formed from outer cells of the embryo.</p>
<p>The process of implantation involves a complex sequence of cellular steps that must progress correctly for pregnancy to occur. </p>
<p>The endometrial tissues have to be reorganised so the blood vessels grow towards the embryo. These vessels then open up to allow blood to flow into blood-filled spaces (called lacunae) that bathe the surface of the placenta. This allows oxygen and nutrients to move from the mother’s to the fetus’s blood supply.<br>
As these connections form, there can be minor bleeding a few days before a menstrual period is due. This is called “implantation bleeding”.</p>
<p>If any of these steps go awry, the embryo may fail to implant, there may be a brief interaction between the embryo and the endometrium that becomes disrupted (a “biochemical pregnancy” or very early miscarriage), or there may be implantation faults that cause a miscarriage some weeks later. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1188930437558820865"}"></div></p>
<h2>What can go wrong?</h2>
<p>The events at implantation have consequences for the rest of the pregnancy. </p>
<p>Even minor defects in the embryo or endometrial interaction at implantation can <a href="https://doi.org/10.3389/fimmu.2019.00478">increase the risk</a> of common pregnancy conditions such as:</p>
<ul>
<li>preterm labour</li>
<li>high blood pressure (preeclampsia)</li>
<li>sub-optimal fetal growth</li>
<li>premature delivery</li>
<li>pregnancy loss.</li>
</ul>
<h2>What conditions affect the endometrium?</h2>
<p>Inflammation is the hallmark of an unhealthy endometrium and contributes significantly to implantation disorders and miscarriage.</p>
<p>Endometritis (infection of the endometrium) and inflammatory fluid from blocked fallopian tubes (hydrosalpinx) can damage endometrial cells. </p>
<p>Dying and damaged cells attract immune cells that attack and engulf them. When damaged or dying cells are in the endometrium (decidua), the placenta doesn’t grow well and the pregnancy can be affected. </p>
<figure class="align-center ">
<img alt="Woman holds. her pelvis" src="https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525109/original/file-20230509-26-5qvg2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Inflammation can contribute to implantation disorders and miscarriage.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/close-up-photo-of-woman-touching-her-abdomen-3958579/">Pexels/Polina Zimmerman</a></span>
</figcaption>
</figure>
<p><a href="https://theconversation.com/au/topics/endometriosis-2405">Endometriosis</a> (endometrial tissue outside the uterus) and <a href="https://theconversation.com/adenomyosis-causes-pain-heavy-periods-and-infertility-but-youve-probably-never-heard-of-it-104412">adenomyosis</a> (endometrial tissue in the muscle of the uterus) also increase inflammation. In these conditions, endometrial cells in the wrong location grow and then die in response to cyclic menstrual cycle hormones. The immune system then has to be activated to clear the dead cells, creating an inflammatory environment. </p>
<p>Autoimmune conditions and metabolic disorders such as diabetes and insulin resistance also activate the immune system and create an inflammatory endometrial environment. These conditions <a href="https://pubmed.ncbi.nlm.nih.gov/36192117/">have been linked</a> to recurrent miscarriage. </p>
<h2>How can you improve your endometrial health?</h2>
<p>There are several things you can do to support a healthy endometrium. </p>
<p>First, manage the lifestyle factors that increase stress on cells and promote inflammation. This will decrease the chances of implantation problems and miscarriage. </p>
<p>Cutting down on <a href="https://academic.oup.com/humrep/article/22/2/543/2939206">smoking</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0890623819300073?via%3Dihub">marijuana</a>, too much <a href="https://academic.oup.com/biolreprod/article/99/6/1266/5049471">coffee</a> or <a href="https://academic.oup.com/humrep/article/36/9/2538/6294415">alcohol</a>, and <a href="https://www.sciencedirect.com/science/article/pii/S0002916522007663?via%3Dihub">avoiding</a> sugary and processed foods will make it easier for the endometrium to stay healthy. </p>
<p>For some women, the diagnosis and treatment of medical conditions that cause inflammation, such as diabetes and autoimmune problems, ensures treatments can start. Treating these conditions can reduce the risk of miscarriage and pregnancy complications.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/considering-using-ivf-to-have-a-baby-heres-what-you-need-to-know-108910">Considering using IVF to have a baby? Here's what you need to know</a>
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<img src="https://counter.theconversation.com/content/202854/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Hull is Professor and leader of the endometriosis and endometrium group at and at the Robinson Research Institute at the University of Adelaide.
She works as a Fertility Specialist (FRANZCOG, CREI) and is also the Medical Director / Owner of Embrace Fertility, Adelaide.
Louise has previously received funding from the Federal Government Grant for the EndoZone project and MRFF Funding for Imagendo.
Louise Hull also works as a Staff Specialist Consultant at the Women's and Children's Hospital Adelaide </span></em></p><p class="fine-print"><em><span>Sarah Robertson receives funding from the National Health and Medical Research Council of Australia, and the Australian Research Council.</span></em></p>Human reproduction is completely dependent on the health of an underestimated but vital organ: the endometrium. Here’s how it works.Louise Hull, Professor and Endometriosis Group Leader, The Robinson Research Institute, University of AdelaideSarah Robertson, Professor and Director, Robinson Research Institute, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1981182023-04-13T15:17:09Z2023-04-13T15:17:09ZPlanning for a baby? Why both men and women should consider quitting alcohol before and during pregnancy<figure><img src="https://images.theconversation.com/files/520784/original/file-20230413-14-lfsl69.jpg?ixlib=rb-1.1.0&rect=65%2C57%2C5390%2C3571&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You might want to make booze a thing of the past.</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/positive-multiethnic-couple-drinking-wine-with-guests-5876657/">pexels/monstera</a></span></figcaption></figure><p>When a couple is planning on having a baby, it’s often the woman who is seen as responsible for the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0749379716000660#bib8">health of the unborn child</a>. </p>
<p>In the UK, the chief medical officer’s <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/545937/UK_CMOs__report.pdf">drinking guidelines</a> recommend that women should abstain from alcohol consumption during pregnancy. This is because it’s known to increase the risk of <a href="https://pubmed.ncbi.nlm.nih.gov/31194258/">miscarriage</a> and <a href="https://www.nhs.uk/conditions/foetal-alcohol-spectrum-disorder/">foetal alcohol spectrum disorders</a> (FASD). </p>
<p><a href="https://theconversation.com/how-foetal-alcohol-spectrum-disorders-could-be-a-hidden-epidemic-52835">FASD</a> is an umbrella term used to describe a range of emotional, behavioural, developmental and learning challenges that are linked to a baby’s <a href="https://theconversation.com/up-to-17-of-children-in-the-uk-could-have-symptoms-of-foetal-alcohol-spectrum-disorder-according-to-latest-estimates-107649">exposure to alcohol</a> while in the womb.</p>
<p>The guidelines also recommend that if you’re planning to become pregnant, the safest approach is <a href="https://theconversation.com/health-risks-of-light-drinking-in-pregnancy-confirms-that-abstention-is-the-safest-approach-83753">not to drink</a> at all to minimise the risks to your pregnancy.</p>
<p>But evidence from large surveys shows that not all women stop drinking before pregnancy – whether the pregnancy was intended or not. In a 2017 <a href="https://pubmed.ncbi.nlm.nih.gov/28277356/">study</a> of 5,036 women in the US, the prevalence of alcohol consumption before pregnancy was similar between those with intended (55%) and unintended pregnancies (56%). </p>
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<figure class="align-right ">
<img alt="Quarter life, a series by The Conversation" src="https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><strong><a href="https://theconversation.com/uk/topics/quarter-life-117947?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">This article is part of Quarter Life</a></strong>, a series about issues affecting those of us in our twenties and thirties. From the challenges of beginning a career and taking care of our mental health, to the excitement of starting a family, adopting a pet or just making friends as an adult. The articles in this series explore the questions and bring answers as we navigate this turbulent period of life.</em></p>
<p><em>You may be interested in:</em></p>
<p><strong><em><a href="https://theconversation.com/five-important-things-you-should-have-learned-in-sex-ed-but-probably-didnt-202177">Five important things you should have learned in sex ed – but probably didn’t</a></em></strong></p>
<p><strong><em><a href="https://theconversation.com/mens-fertility-also-declines-with-age-heres-what-to-know-if-youre-planning-to-wait-to-have-kids-187498">Men’s fertility also declines with age — here’s what to know if you’re planning to wait to have kids</a></em></strong></p>
<p><strong><em><a href="https://theconversation.com/five-things-research-can-teach-us-about-having-better-sex-according-to-a-sex-therapist-199360">Five things research can teach us about having better sex, according to a sex therapist</a></em></strong></p>
<hr>
<p>In another 2015 <a href="https://obgyn.onlinelibrary.wiley.com/doi/10.1111/aogs.12816">study</a> of 3,390 Swedish women, weekly alcohol consumption was not significantly different between women with a “very planned pregnancy” (11%) compared with women with a “very unplanned pregnancy” (14%). </p>
<p>And a 2013 <a href="https://www.tandfonline.com/doi/full/10.3109/13625187.2013.851183">survey</a> of 258 Danish women found that although 77% of their pregnancies were “very” or “fairly well planned”, one out of five reported binge drinking early in the pregnancy. Among women with unplanned pregnancies, this rose to one out of three.</p>
<p>But while the focus tends to be on a woman’s relationship with alcohol before and during pregnancy, an increasing amount of evidence indicates that men’s alcohol use also <a href="https://www.sciencedirect.com/science/article/abs/pii/S0749379716000660#bib8">plays a role</a> when it comes to the health of the baby. </p>
<p>Indeed, alcohol can <a href="https://www.ajog.org/article/S0002-9378(08)02037-1/fulltext">affect sperm DNA</a>, in some cases reducing <a href="https://theconversation.com/how-mens-damaged-sperm-could-play-significant-role-in-recurrent-miscarriage-109683">fertility</a> and the potential to conceive. </p>
<h2>Why stop drinking?</h2>
<p>Better health outcomes for babies <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/729018/Making_the_case_for_preconception_care.pdf">begin before conception</a>, with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4293222/">clear links established</a> between the health of men and women before pregnancy and the health of their offspring. </p>
<p>Research shows that if couples are trying to conceive, it makes sense for them both to quit the booze <a href="https://edition.cnn.com/2019/10/03/health/dads-trying-to-conceive-stop-drinking-wellness/index.html">at least six months before pregnancy</a>. This helps to reduce the risk of potential negative outcomes for the baby such as <a href="https://journals.sagepub.com/doi/abs/10.1177/2047487319874530?journalCode=cprc">congenital heart disease</a>.</p>
<p>It also has <a href="https://www.drinkaware.co.uk/advice/how-to-reduce-your-drinking/the-benefits-of-drinking-less">benefits</a> for the <a href="https://www.drugsandalcohol.ie/32647/1/R-de-Visser-Dry-January-evaluation-2019.pdf">expectant parents</a>, such as better sleep quality, increased energy, and enhanced concentration levels.</p>
<p>Research has also <a href="https://www.sciencedirect.com/science/article/pii/S0749379716000660#bib8">found</a> that if a couple lives together and the male partner drinks, there is a higher chance that the woman will drink alcohol before and during the pregnancy.</p>
<p>One of the reasons why this might be the case is explored in <a href="https://journals.sagepub.com/doi/full/10.1177/1757975912441225">another study</a> where women said that drinking with a partner, whether before or during pregnancy, provided a sense of social connection.</p>
<figure class="align-center ">
<img alt="Pregnant woman holding belly." src="https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/515255/original/file-20230314-3238-lcctzb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">It’s best to avoid alcohol altogether if you are wanting to conceive.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/smiling-pregnant-woman-caressing-tummy-in-house-room-5427247/">Pexels/Amina Filkins</a></span>
</figcaption>
</figure>
<p>The period before pregnancy, known as preconception, is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5975952/pdf/emss-77899.pdf">window of opportunity</a> for would-be parents to improve their health and increase their likelihood of conceiving. And <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/729018/Making_the_case_for_preconception_care.pdf">alcohol consumption</a> should be thought about as part of this. </p>
<p>As part of our recent research, we <a href="https://www.sciencedirect.com/science/article/pii/S2772653322000405?via=ihub">reviewed the literature</a> exploring people’s and health professionals’ views about information and support for reducing drinking in the period before getting pregnant. </p>
<p>We found that women were aware that lifestyle factors such as smoking or drinking alcohol can affect their pregnancy and increase the risk of poor outcomes for the baby. But there was a notable lack of awareness of the importance of men reducing their alcohol consumption when planning for pregnancy, too. </p>
<p>Indeed, men <a href="https://www.jabfm.org/content/jabfp/26/2/196.full.pdf">don’t usually go to clinics</a> to get information about preconception health, as this is usually left to the woman. </p>
<h2>Quit together</h2>
<p>While there is some indication that men, as well as women, are open to changing their drinking behaviour when planning for pregnancy, our literature review found that <a href="https://www.sciencedirect.com/science/article/pii/S1877575617300940?via=ihub">very few studies</a> have explored men’s or partners’ views on preconception health.</p>
<p>And while there are promising results from interventions and approaches aimed at enhancing preconception health in men and women, such as <a href="https://www.sciencedirect.com/science/article/pii/S1877575617300940?via=ihub">alcohol screening</a> followed by counselling and health education on <a href="https://www.sciencedirect.com/science/article/pii/S1877575617300940?via=ihub">changing behaviour</a>, there’s still not enough emphasis placed on men’s health at the preconception stage. This needs to change because, as the research shows, a baby’s health is influenced by both mum and dad. </p>
<p>So if you are considering trying for a baby, now could be the time for both partners to set new goals and <a href="https://www.nhs.uk/pregnancy/keeping-well/drinking-alcohol-while-pregnant/">cut down on drinking</a> together. And if you’re concerned about the amount you drink, or are dependent on alcohol, you should get <a href="https://www.nhs.uk/conditions/alcohol-misuse/treatment/">professional advice and support</a> on cutting down safely.</p>
<hr>
<p><em><strong>Other Quarter Life articles you may be interested in:</strong></em></p>
<p><strong><em><a href="https://theconversation.com/ivf-add-ons-why-you-should-be-cautious-of-these-expensive-procedures-if-youre-trying-to-conceive-180198">IVF add-ons: why you should be cautious of these expensive procedures if you’re trying to conceive</a></em></strong></p>
<p><strong><em><a href="https://theconversation.com/anxiety-can-lead-to-erection-problems-in-young-men-but-reaching-for-viagra-isnt-always-the-solution-191980">Anxiety can lead to erection problems in young men – but reaching for Viagra isn’t always the solution</a></em></strong></p>
<p><strong><em><a href="https://theconversation.com/young-people-are-drinking-less-heres-an-alternative-to-try-on-your-next-night-out-197465">Young people are drinking less – here’s an alternative to try on your next night out</a></em></strong></p><img src="https://counter.theconversation.com/content/198118/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>We would like to thank Lisa Schölin, Queens Medical Research Institute, University of Edinburgh; Andrea Hilton, Department of Paramedical, Perioperative and Advanced Practice, University of Hull and Anand Ahankari, Faculty of Health and Medical Sciences, University of Surrey who are part of the research team and helped with writing and reviewing this article.</span></em></p><p class="fine-print"><em><span>Lesley Smith received funding from the National Institute of Health Research, The Institute of Alcohol Studies, the former Alcohol Research UK (now Alcohol Change UK) and The Joseph Rowntree Foundation for alcohol-related research. </span></em></p><p class="fine-print"><em><span>Jayne Walker does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Cutting down on alcohol consumption before pregnancy can benefit the health of both men, women and their baby.Lolita Alfred, Lecturer in Mental Health, School of Health and Psychological Sciences, City, University of LondonJayne Walker, Senior lecturer| Professional Lead. School of Paramedical, Peri-Operative and Advanced Practice. Faculty of Health Sciences., University of HullLesley Smith, Professor of Women's Public Health, Institute of Clinical and Applied Health Research, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1904472022-12-16T00:40:16Z2022-12-16T00:40:16ZCurious Kids: how are babies made?<figure><img src="https://images.theconversation.com/files/498841/original/file-20221205-26-5mon89.jpg?ixlib=rb-1.1.0&rect=131%2C23%2C5044%2C3088&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/photo-of-new-born-baby-covered-with-blue-blanket-3617844/">Pexels/Laura Garcia</a></span></figcaption></figure><blockquote>
<p>How are babies made? Giaan, age 8</p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Thanks for your interesting question, Giaan! </p>
<p>Lots of kids your age wonder about how babies are made. It’s an important question because making babies allows the human species (and other animals) to continue.</p>
<h2>Knowing the body parts</h2>
<p>The first step in making a baby happens when a sperm from a man’s body joins with an egg from a woman’s body. </p>
<p>To understand how this happens, it is helpful to know the proper names for different body parts. These <a href="https://www.nationwidechildrens.org/family-resources-education/health-wellness-and-safety-resources/helping-hands/body-system-reproductive-female">pictures</a> <a href="https://www.nationwidechildrens.org/family-resources-education/health-wellness-and-safety-resources/helping-hands/body-system-reproductive-male">may help</a>.</p>
<p>When I say man, I’m referring to a person with a penis and testes (sometimes called testicles).</p>
<p>When I say woman, I’m referring to a person with a uterus (where the baby grows), vagina (the passage inside the vulva that leads to the uterus), and ovaries.</p>
<p>But sometimes, people are born with differences in these body parts. And sometimes these body parts don’t match how people think of themselves – as a man or woman or non-binary person.</p>
<h2>Where do the sperm and egg come from?</h2>
<p>Puberty is the time when your body begins to develop, and changes from child to adult, usually in later primary school and early high school years.</p>
<p>Sperm look a bit like tadpoles but are so small that you need a microscope to see them. They are made in the man’s testes and are released in a liquid called semen.</p>
<p>Once a boy goes through puberty, their testes can produce millions of sperm each day.</p>
<figure class="align-center ">
<img alt="Scientist looks through a microscope" src="https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=438&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=438&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=438&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=550&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=550&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498897/original/file-20221205-12013-hevoyr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=550&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sperm are so small you’d need a microscope to see them.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/woman-scientist-looking-through-microscope-laboratory-341424821">Shutterstock</a></span>
</figcaption>
</figure>
<p>Eggs are stored in the woman’s ovaries and after puberty there is usually one egg released per month. </p>
<p>An egg is just big enough to see – it’s about the size of a grain of sand (still pretty small!).</p>
<h2>How do the sperm and egg join?</h2>
<p>So how do the sperm and egg join to make a baby? This is called conception.</p>
<p>The most common way conception happens is when a woman and a man have sexual intercourse. This means that the man’s penis goes inside the woman’s vagina and semen squirts out. </p>
<p>Sperm come out of the penis and go up into the vagina and if one of the sperm connects with an egg, the two may combine to make a baby (actually, it’s called an embryo at this stage). </p>
<figure class="align-center ">
<img alt="Sexual reproduction graphic" src="https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=416&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=416&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498869/original/file-20221205-17-4ytnw7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=416&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The sperm and egg combine to make an embryo, which grows into a baby.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/sexual-reproduction-stages-steps-levels-fertilization-1883185015">Shutterstock</a></span>
</figcaption>
</figure>
<p>The embryo makes its way to the uterus, where it will grow for the next nine months, until the baby is ready to be born.</p>
<h2>Babies can be conceived in other ways too</h2>
<p>Some families have two mums, and they may ask a man to provide sperm (called a sperm donor). The doctor places the sperm in the uterus of one of the mums.</p>
<p>There is also a process called IVF (in-vitro-fertilisation). For this, doctors take sperm from a man and an egg from a woman and combine them in a dish to form an embryo. </p>
<p>Then the embryo is put inside the woman’s uterus by the doctor and continues to grow there, just like other babies. </p>
<h2>OK, then what happens?</h2>
<p>After the egg and sperm join to make an embryo, the embryo attaches to the mother’s uterus. </p>
<p>An organ called the placenta forms to supply the growing baby with all the nutrition it needs. </p>
<figure class="align-center ">
<img alt="Fetus and placenta in a uterus" src="https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=443&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=443&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=443&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498834/original/file-20221205-26-iuc4zp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The placenta, shown here on the right, feeds the baby while it’s in its mother’s uterus.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/baby-womb-placenta-1093421162">Shutterstock</a></span>
</figcaption>
</figure>
<p>When the baby is ready to be born, the muscles of the mum’s uterus start to contract and push the baby out through the vagina. </p>
<p>Some babies can’t be safely pushed out through the vagina and are delivered by an operation where a doctor removes the baby through a cut below the mum’s belly button (called a caesarean or c-section). During the operation, the doctor gives the mum a special injection in her back to take the pain away.</p>
<h2>Have more questions? Kids often do</h2>
<p>Often kids have more questions to ask about some of the things discussed in this article. Some kids want to know a lot more and others maybe just a couple of things. </p>
<p>If you have more questions, then have a chat with mum, dad, or another trusted adult, such as a teacher. <a href="https://www.healthywa.wa.gov.au/%7E/media/HWA/Documents/Healthy-living/Sexual-health/talk-soon-talk-often.pdf">Here is</a> a good resource for them to look at if they are unsure about how much to explain.</p><img src="https://counter.theconversation.com/content/190447/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bianca Cannon does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Lots of kids wonder about this. Here are some of the basics.Bianca Cannon, GP and Lecturer at Sydney Medical School, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1869842022-08-05T12:10:37Z2022-08-05T12:10:37Z500K American men get vasectomies every year – a specialist explains the easy and reversible procedure<figure><img src="https://images.theconversation.com/files/475921/original/file-20220725-20-yvadro.jpg?ixlib=rb-1.1.0&rect=0%2C14%2C4915%2C3664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This year, many vasectomy patients are young or single men concerned about unwanted pregnancy at a time when abortion care may not be as available as before.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/doctor-in-discussion-with-patient-in-exam-room-royalty-free-image/97863283">Thomas Barwick/Stone via Getty Images</a></span></figcaption></figure><figure class="align-center ">
<img alt="Green plate reading: 500,000 Number of men in the US who undergo vasectomies each year" src="https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/474983/original/file-20220719-4704-cux94h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p>About half a million men undergo a vasectomy in the United States in any given year. The percentage of men getting them had been <a href="https://doi.org/10.1111/andr.13093">dropping for the past two decades</a>, but it looks like those numbers are going up in the wake of the June 24, 2022, Supreme Court <a href="https://www.oyez.org/cases/2021/19-1392">decision overturning Roe v. Wade</a>. </p>
<h2>Appointments up</h2>
<p>It’s too early for official numbers, but as a urologist and <a href="https://doctors.umiamihealth.org/provider/Ranjith+Ramasamy/526160">microsurgeon specializing in vasectomies</a>, I can report that more new patients are coming to see me. We used to perform about 20-25 vasectomies a month in our Miami clinic. But since the Dobbs v. Jackson decision came down, we’re now fully booked at 30 vasectomies scheduled each month through next year. I’m also seeing about 30% more online queries about vasectomies. It’s the first such increase I’ve seen in my 15-year career.</p>
<p>Other <a href="https://www.newsweek.com/male-contraception-vasectomies-inquiries-increase-roe-v-wade-supreme-court-1724739">urologists have rising numbers, too</a>. One Kansas City doctor said that he had <a href="https://www.cbs19news.com/story/46797913/urologist-says-vasectomy-consults-have-increased-by-900-since-roe-v-wade-decision">a 900% increase in vasectomy inquiries</a> in just the four days after the decision.</p>
<p>Most of our clinic’s new vasectomy patients are young or single men. They tell me they are concerned about getting a woman pregnant when abortion care isn’t as available as it was before. They also ask about <a href="https://doi.org/10.1007/978-3-030-47767-7_36">freezing their sperm first</a> in case they want biological children in the future. <a href="https://doi.org/10.1007/s10815-022-02545-6">Frozen storage is a viable option</a>, and some patients have even <a href="https://doi.org/10.1093/humrep/deac107.023">successfully frozen their own sperm</a>. </p>
<h2>Quick and simple</h2>
<p>Most vasectomies are straightforward, with 98% of them performed <a href="https://www.urologyhealth.org/educational-resources/vasectomy">in an outpatient clinic</a>. For the duration of the 15- to 20-minute procedure, most men are <a href="https://doi.org/10.1016/j.juro.2012.09.080">wide awake in a medical office</a>.</p>
<p>Only 2% of vasectomy patients get them in a hospital under anesthesia. That’s usually because of anatomical issues or previous surgeries complicating the procedure – or the personal preference of the patient to go to sleep.</p>
<p>The doctor starts by making a small opening in the scrotum. Then the doctor pulls out the vas deferens, the tube that delivers sperm out of the testes and to the ejaculatory duct. After placing permanent clips on the tube in two places, the doctor removes a small piece of tube between the clips. The clips remain in place, closing and permanently sealing the cut tube ends. Now there is no longer any connection between the testes where sperm is produced and the urethra, where it once exited the body. </p>
<p>Patients usually go home and recover for about four hours with some ice on the area. Most can go back to work a day or two later if their job doesn’t involve manual labor. We recommend no sex and no heavy lifting for about a week after the vasectomy.</p>
<p>The recovery period is a popular excuse for sports fans to plan their vasectomy around <a href="http://doi.org/10.21037/tau.2019.08.33">major sports events on TV</a> so that while they heal they can watch the Masters golf tournament, baseball’s World Series or the bowl games of American football. In fact, “March Madness vasectomy” promotions timed to college basketball playoffs are among the reasons <a href="https://doi.org/10.1016/j.urology.2018.03.016">March is a popular month</a> for appointments.</p>
<h2>More concerns than changes</h2>
<p>About two to three months later, the patient returns to the clinic. We take a sample of semen to check the sperm count. That tells us whether his vasectomy was successful. If any sperm are in the ejaculate, we might need to do a second one, but that happens in <a href="https://doi.org/10.21037%2Ftau.2017.07.08">fewer than 1% of cases</a>. Most of the time, we can give the patient the all-clear that their procedure is complete.</p>
<p>Of course, this is a surgery, so patients naturally have significant questions and concerns. A common one I’ll hear from a patient is that getting a vasectomy will make him “less of a man” because he is no longer able to father children. But that is absolutely not true. It won’t make you less of a man. </p>
<p>Some men fear it will damage their penis because the procedure is so close to it. But a vasectomy will not damage a man’s penis or any other surrounding structures. And he will not have any changes in sexual function or enjoyment after recovery from the procedure. </p>
<p>While everything else is the same as before, ejaculate volume obviously decreases slightly after a vasectomy. This worries some men. But it’s not a noticeable decrease, since <a href="https://onlinelibrary.wiley.com/doi/10.1111/andr.12983">sperm is only 5% of semen volume</a>. </p>
<p>If patients do change their minds, however, they can get their vasectomies reversed, and <a href="https://doi.org/10.1016/j.urology.2018.03.016">about 5% of U.S. patients do</a>.</p>
<p>Most commonly this involves a man with a new partner who wants to have biological kids. Nearly all vasectomy reversals succeed, with sperm returning to the ejaculate <a href="https://doi.org/10.1016/j.urology.2018.03.016">90% to 95% of the time</a>. And pregnancies follow vasectomy reversals about 50% to 60% of the time, depending on the age of the woman.</p><img src="https://counter.theconversation.com/content/186984/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ranjith Ramasamy receives funding from Acerus Pharmaceuticals (Consultant, Grant Recipient), Boston Scientific (Consultant, Grant Recipient), Coloplast (Consultant, Grant Recipient), Endo Pharmaceuticals (Consultant, Grant Recipient), Empower Pharmacy (Grant Recipient), Nestle Health (Consultant), Olympus (Grant Recipient), Hims, Inc (Advisory Board). </span></em></p>As more younger, single men ask for one following the Supreme Court abortion decision, a urologist explains what to expect with a vasectomy.Ranjith Ramasamy, Associate Professor of Urology, University of MiamiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1846592022-07-28T14:35:42Z2022-07-28T14:35:42ZShining fluorescent light on bee sperm could help explain colony survival<figure><img src="https://images.theconversation.com/files/467758/original/file-20220608-20-fs4cf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Ivan Marjanovic/Shutterstock</span></span></figcaption></figure><p>Form follows function. This is the principle that the design or shape of something – whether made by humans or in nature – should serve a purpose.</p>
<p>Honey bees’ function is to pollinate plants, make honey, survive and reproduce. Along with other pollinators – birds, moths, butterflies, bats and many more – they are the unsung forces behind much of what people eat, drink and even wear. Animal pollinators are said to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8396518/">contribute</a> to the production of 87 global crops in 200 countries, including 30% of the world’s food crops. Their labours have been valued at around 153 billion euros.</p>
<p>But in one <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320718313636">review paper</a>, researchers suggest that at current rates of decline, the world will lose some 40% of its insect species, including bees, over the next few decades. Among the causes are widespread use of <a href="https://www.reuters.com/article/us-science-europe-pesticides/pesticides-put-bees-at-risk-european-watchdog-confirms-idINKCN1GC18G">pesticides</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320718313636">habitat loss</a>.</p>
<p>Bee colonies are collapsing around the world. In Europe, a <a href="https://ec.europa.eu/food/system/files/2017-04/la_bees_epilobee-report_2012-2014.pdf">2012-2014 survey</a>, the first of its kind, by the European Commission estimated that some countries were losing as many as a third of their colonies every year.</p>
<p>The threats to their survival make it urgent to understand the relationship between form and function in honey bees, particularly the sperm of the male bees (drones) – the “<a href="https://www.smithsonianmag.com/science-nature/key-honey-bee-conservation-bee-semen-180969676/">flying genitalia</a>” of the bee world, as one researcher described them. That’s because of the way bees mate and reproduce.</p>
<p>Researchers around the world are applying the latest technologies to this project. One technique is computer-aided sperm analysis. This assesses sperm function (its vitality and movement) and its structural parameters. At the comparative spermatology group at the University of the Western Cape in South Africa, we have a particular interest in the structure and movement of insect sperm. We’ve now <a href="https://doi.org/10.1080/00218839.2022.2090729">pioneered</a> the use of fluorescent microscopy in combination with computer-aided sperm analysis for what we believe are superior results.</p>
<p>In addition to motility and velocity, our in-depth analyses provide data on, among other things, the swimming patterns of honey bee sperm. This fluorescent method shows promise and can, <a href="https://doi.org/10.1080/00218839.2022.2090729">we argue</a>, provide baseline data for future studies evaluating honey bee sperm quality. </p>
<p>This matters as we seek to secure the survival of honey bee colonies.</p>
<h2>Choosy queen bees</h2>
<p>For now, South Africa and African honey bees appear to have been spared the colony losses seen in some parts of the world. This is thanks to the continuing use of traditional beekeeping practices, according to a <a href="https://www.fao.org/3/i2462e/i2462e.pdf">2012 report</a> by the United Nations’ Food and Agricultural Organisation.</p>
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Read more:
<a href="https://theconversation.com/lessons-from-africa-on-how-to-build-resilient-bee-colonies-131478">Lessons from Africa on how to build resilient bee colonies</a>
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<p>But the threat, as evidenced by the situation in Europe, can’t be ignored. </p>
<p>There is some urgency to understanding the sperm quality of the honey bee drones because of how long it has to last. Bee queens have limited mating flights. They fly to what’s known as a drone congregation area and mate with multiple drones before heading back to the colony. The queen <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718501/#:%7E:text=Honeybee%20queens%20are%20efficient%20sperm,on%20the%20honeybee%20mating%20system">can store</a> some six million sperm in a specialised sac, the spermatheca, for as long as seven years. Any one queen bee can potentially have around 1.7 million offspring.</p>
<p>So, she needs the best and most resilient sperm she can get. And she will be choosy, shedding some sperm and keeping only what she likes. It’s not known how the queen decides which sperm is chosen or shed. </p>
<p>This is where form and function meet. Honey bee sperm has a very long tail, about 225 micrometres (µm) in length. It dwarfs the tails of the sperm of larger vertebrates, which are typically in the 40-75 µm range.</p>
<p>Why these long tails? Do they aid motility – how strongly and how fast the sperm moves? Are they relevant to the sperm’s longevity in the queen’s sperm sac? Do they determine which sperm the queen decides to hold on to and which to shed?</p>
<p>To answer these questions, we need the right technology. </p>
<h2>Technology sheds light</h2>
<p>Honey bee sperm are devilishly difficult to study, even with powerful microscopes and tried-and-tested techniques such as <a href="https://www.microscopyu.com/techniques/phase-contrast/introduction-to-phase-contrast-microscopy">phase-contrast microscopy</a>, a technique that allows more contrast in a viewed sample. This has much to do with the sperm’s form and structure. The tails are often tightly coiled in a helix, making it hard to tell which is the tail and which the head of the sperm. Both have about the same width. </p>
<p>Other studies of sperm motility and kinematic parameters – broadly, the direction and range of movement – have tried to work around these blind spots, but at the expense of thorough analysis.</p>
<p>Our research group has adapted and stacked existing technology to study the sperm of the <a href="https://pubmed.ncbi.nlm.nih.gov/31383288/">black soldier fly</a> and <a href="https://www.micropticsl.com/bee-sperm-2/">the Cape honey bee</a>. </p>
<p>In our <a href="https://doi.org/10.1080/00218839.2022.2090729">first published paper</a> about this work, we explain how we have improved on other sperm analysis systems by using fluorescence. This has also been done successfully in studies of human sperm. Only sperm heads fluoresce – glow brightly – so it is much simpler to distinguish head from tail.</p>
<p>This has allowed us to glean useful insights into sperm concentration among drones. We’ve also been able to confirm the three swimming patterns of sperm: moving in single helices (wound-up), progressively forward snake-like swimmers, and what we describe as groups of helical swimming sperm (as compared to the individual helical swimmers).</p>
<h2>Protecting colonies</h2>
<p>Sperm quality has also been put forward as a cause of colony collapse. This sort of research broadens our understanding of sperm quality’s importance for colony health and performance. Researchers elsewhere have <a href="https://doi.org/10.1093/jisesa/ieab048">suggested</a> that drone quality (which we believe includes sperm quality) and variability in a colony or apiary can be a useful indicator of queen and colony health. It can therefore also be used to identify the effect of, for example, environmental stressors. </p>
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Read more:
<a href="https://theconversation.com/what-honeybees-in-south-africa-need-from-people-better-managed-forage-166369">What honeybees in South Africa need from people: better managed forage</a>
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<p>Assessing sperm quality as part of drone quality will allow for early detection of such stressors. That will allow for preventive management strategies to avoid colony deterioration.</p>
<p>We still have much to learn about honey bee sperm and colony collapses. But if it means we can aid beekeepers to track colony health, for instance, perhaps we can help to secure the future of this critical pollinator. </p>
<p><em>The research on which this article is based was co-authored by Master’s student Janice Murray. Mike Allsopp of the Agricultural Research Council helped to collect data in the field.</em></p><img src="https://counter.theconversation.com/content/184659/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christina Kotze receives funding from National Research Foundation (NRF); Thuthuka funding instrument; Grant number: TTK180407318351.
</span></em></p><p class="fine-print"><em><span>Gerhard van der Horst is an Emeritus Professor of Medical Bioscience at UWC and an Extra-Ordinary Professor at the University of Stellenbosch. He is also a senior consultant to Microptic SL, Barcelona, Spain in the field of Computer Aided Sperm Analysis</span></em></p>Studying bee sperm is difficult because of the way it coils, but fluorescent light illuminates the head of the sperm. Sperm quality may indicate stress levels in the bee colony.Christina Kotze, Lecturer in anatomy and physiology, and researcher in invertebrate reproductive biology, University of the Western CapeGerhard van der Horst, Emeritus Professor UWC, Extra-Ordinary Professor SU, expert comparative spermatologist, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1785042022-04-26T19:53:33Z2022-04-26T19:53:33ZExtreme heat waves threaten honeybee fertility and trigger sudden death<p>Temperatures soared above 42 C for days in Western Canada in June 2021, with Lytton, B.C., registering 49.6 C, <a href="https://www.rmets.org/metmatters/record-breaking-heat-canada">the hottest temperature ever recorded in Canada</a>. Wildfires scorched the province, sparking a <a href="https://www2.gov.bc.ca/gov/content/safety/wildfire-status/about-bcws/wildfire-history/wildfire-season-summary">56-day state of emergency</a> and <a href="https://www2.gov.bc.ca/assets/gov/birth-adoption-death-marriage-and-divorce/deaths/coroners-service/statistical/heat_related_deaths_in_bc_knowledge_update.pdf">nearly 600 additional sudden deaths</a> compared to the same time in 2020.</p>
<p>But humans were not the only ones affected by the heat. Beekeepers in the Okanagan Valley reported <a href="https://alisonmcafeeblogs.wordpress.com/2022/01/19/research-bulletin-keeping-nucs-cool-in-a-heatwave/">unusual deaths of honeybee queens, drones and small colonies</a>. Drones, which are the reproductive males, <a href="https://news.ubc.ca/2022/02/22/bees-are-explosively-ejaculating-to-death-a-polystyrene-cover-could-help-stop-it/">spontaneously ejaculate</a> when they die from stress, and Emily Huxter, a beekeeper in Armstrong, <a href="https://focus.science.ubc.ca/bee-ting-the-heat-65679c3be719">saw dozens of drones</a> suddenly lying dead on the lids of her hives with their male bits poking out. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=247&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=247&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=247&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=311&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=311&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451688/original/file-20220312-25-1agjimo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=311&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A honeybee drone that died during the heat wave in British Columbia in June 2021.</span>
<span class="attribution"><span class="source">(Emily Huxter)</span></span>
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<p>I research how heat stress affects honeybees, and Huxter’s observations reflect what I’ve seen in the lab. Our experiments show that after six hours at 42 C, <a href="https://doi.org/10.1038/s41893-020-0493-x">50 per cent of male honeybees die</a>. The results were alarming, yet conservative compared to previous work. <a href="https://doi.org/10.1093/beheco/art049">Other researchers</a> have found that up to 77 per cent of drones die from exposure to 42 C for just four hours. </p>
<p>This means that after a heat wave, new queens — the reproductive females — will have fewer opportunities to mate. Colonies headed by poorly mated queens are <a href="https://doi.org/10.1007/s00114-013-1065-y">more likely to collapse</a>, and this could pose problems for farmers who rely on honeybees to pollinate their crops. But it also betrays the risk that heat waves pose to populations of wild insects. </p>
<h2>Death isn’t the only damage</h2>
<p>Worryingly, male fertility likely begins to decline well before the drones die. For example, after just two hours at 42 C, about <a href="https://doi.org/10.1038/s41893-020-0493-x">one-third</a> of sperm cells within drone ejaculates perish. This means that if a male bee survives a heat event, his fertility is likely impaired. Huxter’s dead drones indicate that the temperatures last summer clearly reached the fertility-damaging range, even for those that survived.</p>
<p>Queen honeybees mate and keep sperm in a specialized storage organ over their lifetime, typically <a href="https://doi.org/10.1016/s0531-5565(00)00236-9">one to three years</a>. But even stored sperm cells are not safe from hot temperatures. Queens exposed to temperatures above 38 C for two hours or more usually survive, but the viability of the stored sperm drops to what beekeepers consider to be “<a href="https://doi.org/10.1038/s42003-020-01586-w">poor quality</a>.”</p>
<p>Large, established colonies appeared to fare well during the 2021 heat dome, in terms of survival. But just because most bees survived, this insidious loss of fertility for both drones and queens means that they could still have been harmed.</p>
<figure class="align-center ">
<img alt="Queen honey bee" src="https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=502&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=502&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=502&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=631&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=631&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451685/original/file-20220312-26-12odmtz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=631&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Canada imports about 250,000 queen honeybees each year.</span>
<span class="attribution"><span class="source">(Alison McAfee)</span></span>
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<h2>Wild insects matter too</h2>
<p>Honeybees are not the only insects whose fertility is impacted by extreme heat. Scientists expect that <a href="https://www.nationalacademies.org/based-on-science/global-warming-makes-heat-waves-hotter-longer-and-more-common">worsening heat waves</a> could impair fertility of <a href="https://doi.org/10.1038/s41467-018-07273-z">beetles</a>, <a href="https://doi.org/10.1111/1365-2435.13738">bumblebees</a>, <a href="https://doi.org/10.1111/j.1420-9101.2005.00914.x">flies</a>, <a href="https://doi.org/10.1016/j.jinsphys.2017.09.004">moths</a> and <a href="https://doi.org/10.1016/j.jinsphys.2012.12.001">wasps</a> — and those are just some of the ones we know about. </p>
<p>For whole populations, the trends are even more concerning. In the flour beetle, <em>Tribolium castaneum</em>, the sons of heat-stressed fathers can have impaired fertility, despite never having experienced the heat themselves. Scientists predict widespread <a href="https://doi.org/10.1126/science.aax8591">wild bumblebee declines</a> as the frequency of heat events increase to “untenable” extremes. And the temperatures at which male fruit flies lose their fertility do a better job of <a href="https://doi.org/10.1038/s41558-021-01047-0">explaining their geographic distributions</a> than the <a href="https://www.nature.com/scitable/knowledge/library/physiological-optima-and-critical-limits-45749376/">hottest temperatures at which they can survive</a> do.</p>
<figure class="align-center ">
<img alt="Bumble bee on blueberry flowers" src="https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451746/original/file-20220313-20-1lyio88.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Honeybees are often used for blueberry pollination, but wild bumblebees are excellent pollinators too.</span>
<span class="attribution"><span class="source">(Alison McAfee)</span></span>
</figcaption>
</figure>
<p>But honeybees can adapt to their environment, and with the help of beekeepers, they will probably adapt to hotter temperatures too. Subspecies from the Middle East have a <a href="https://saudibi.com/file/research_folder/Tolerance_of_two_honey_bee_races_to_various_temperature_and_relative_humidity_gradients.pdf">higher tolerance</a> to hot and arid conditions than those native to Europe, for example, whereas colonies propagated in Canada show <a href="https://doi.org/10.1371/journal.pone.0011096">evidence of selection</a> for cold tolerance. </p>
<p>Even so, honeybee colonies only produce new queens about once a year when they prepare to swarm, or produce a new colony. This means that, relative to quickly reproducing insects like mosquitoes, they are by this metric disadvantaged for adapting to rapidly changing conditions. </p>
<p>Luckily, queen honeybees can compensate for this disadvantage by mating with multiple males, assuming they have not been killed in a recent heat wave. This increases the genetic diversity of their colonies, which is the fodder on which natural selection acts. </p>
<p>Canadian beekeepers also import around <a href="https://dx.doi.org/10.1093%2Fjee%2Ftoaa102">250,000</a> queens each year, adding a constant flow of new genetics. These days, the queens mainly arrive from California and Hawaii, but other exporters include Chile, Australia, Ukraine and New Zealand, among others. This may be a benefit or a hindrance, depending on how genetic diversity balances with local adaptation, but it does promote new combinations of genes that could help deal with new challenges. </p>
<h2>Bees are the bellwethers</h2>
<p>Despite the losses noted by beekeepers, honeybees, as a species, will almost certainly persist as the climate changes. But not all insects will be so lucky. Bumblebee, wasp and many ant queens, which are also produced annually during the summer, <a href="https://doi.org/10.1146/annurev.en.31.010186.001501">generally mate with one or a few males</a>, with limited opportunities for gene flow, and may be less capable of adapting. </p>
<p>Heat waves are clearly not the only challenge insects face: <a href="https://doi.org/10.3389/fevo.2022.847997">Habitat loss, pesticides and pathogens are also important</a>. And two months after British Columbia lifted the state of emergency, <a href="https://www.cbc.ca/news/topic/Tag/B.C.%20Floods%202021">a devastating flood</a> displaced families yet again, as well as untold numbers of native bees hibernating in the ground. </p>
<p>Insects are critical players in ecosystems around the world, and with <a href="https://doi.org/10.1126/science.aax9931">many terrestrial species already declining</a>, research on how climate change will impact their fertility is vital. We pay attention to honeybees because we rely on them for pollinating crops, but they are not the only ones on which we depend. We know that the conditions during the 2021 heat dome are sufficient to reduce fertility of honeybees, which should raise alarm bells about the wild insects who don’t have keepers.</p><img src="https://counter.theconversation.com/content/178504/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alison McAfee receives funding from Project Apis m., the Boone Hodgson Wilkinson Trust Fund, the Eastern Apicultural Society, and the Canadian Bee Research Fund. She is also an active member of the Canadian Association of Professional Apiculturists and is on the research committee for the British Columbia Honey Producers' Association.</span></em></p>Beekeepers in British Columbia reported honeybee deaths during the 2021 heat dome. Other insects may also be at risk.Alison McAfee, Postdoctoral Fellow, Michael Smith Laboratories, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1739792022-01-06T14:39:16Z2022-01-06T14:39:16ZGreat balls of fire: How heating up testicles with nanoparticles might one day be a form of male birth control<figure><img src="https://images.theconversation.com/files/439249/original/file-20220103-36920-yu4j17.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C9485%2C5800&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Warming the testicles using nanorods affects sperm production.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 175px; border: none; position: relative; z-index: 1;" allowtransparency="" src="https://narrations.ad-auris.com/widget/the-conversation-canada/great-balls-of-fire--how-heating-up-testicles-with-nanoparticles-might-one-day-be-a-form-of-male-birth-control" width="100%" height="400"></iframe>
<p>Women have a variety of methods for contraception, but only two methods are commonly available to men: condoms and vasectomies. Both methods have their drawbacks. </p>
<p>Condoms can break, and some men <a href="https://doi.org/10.1111/j.1600-0536.1989.tb03173.x">are allergic to the latex in standard condoms</a>. Vasectomies are surgical procedures that can be <a href="https://dx.doi.org/10.4103/1008-682X.175090">painful</a> and <a href="https://dx.doi.org/10.4103/1008-682X.175091">difficult to reverse</a>. </p>
<p>So the search for <a href="https://dx.doi.org/10.4103/2230-8210.102991">alternative male contraceptive options continues</a>, and one method currently being investigated is <a href="https://doi.org/10.1038/nmat3701">nanocontraception</a>.</p>
<h2>An on/off switch</h2>
<p>Nanocontraception is based on the idea that nanoparticles — here, about 100 nanometres in diameter, or roughly one-thousandth the width of a piece of paper or of a strand of human hair — can somehow be delivered to the testicles, where they can be warmed.</p>
<p>If you could warm up the testicles just a bit, you would have a way to turn sperm production on and off at will because the warmer they get, <a href="https://doi.org/10.1530/jrf.0.1140179">the less fertile they become</a>. But it’s a delicate process because the testicles can be irreversibly destroyed if they become too warm; the tissue dies and can no longer produce sperm, even when the testicles return to their normal temperature.</p>
<p>Using nanotechnology to warm testicles was first studied in 2013 on mice by biologist Fei Sun and his multidisciplinary research team. His early experiments <a href="https://doi.org/10.1021/nl400536d">involved injecting nanoparticles directly into mouse testicles</a>. These nanoparticles were long nanorods (or nanocylinders) of gold atoms — imagine a tube 120 gold atoms long with a diameter of 30 gold atoms — coated with a few long polymer chains on their surface. They looked like oblong bacteria with hairs sticking out.</p>
<p>Infrared radiation was then used on the mice’s testicles. This caused the nanoparticles to warm from around 30 C to between 37 and 45 C. The exact temperature depended on both the concentration of nanoparticles injected and the intensity of the radiation.</p>
<p>The radiation caused heat lesions on the skin surrounding the mice’s testicles, so it was assumed that this procedure was painful for the animals, even though there was no reliable way to measure their pain. The researchers decided to look for other ways to inject the nanoparticles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A hand wearing a latex glove holds a white lab mouse" src="https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers used mice to test nanotechnology as a method of male birth control.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Iron rods</h2>
<p>In July 2021, Sun’s team <a href="https://doi.org/10.1021/acs.nanolett.1c02181">published a paper on their latest findings</a>. The nanorods in the new method are composed of magnetic iron oxide instead of gold, and they are coated with citric acid instead of ethylene glycol — but they have the same size and shape as the earlier nanorods.</p>
<p>These magnetic nanoparticles were injected into mice’s veins, and then the animals were anesthetized. A magnet was then placed next to their testicles for four hours, drawing the nanoparticles there.</p>
<p>This procedure — injection followed by magnetic targeting — was performed daily for one to four days.</p>
<p>After the last day of treatment, an electric coil was wrapped around the testicles, through which a current was passed. This induced a magnetic field that heated up the nanorods and, therefore, the testicles. Similar temperature increases — from a baseline of 29 C to between 37 and 42 C — were observed through this method. The more days a mouse had been injected with nanorods, the hotter its testicles became.</p>
<p>Hotter testicles led to their atrophy and shrinkage, but they showed gradual recovery both 30 and 60 days after treatment as long as testicle temperatures didn’t reach 45 C. Fertility was down seven days after treatment — in some cases, fertility was completely eliminated — but it also showed gradual (though not complete) recovery after 60 days.</p>
<p>Although fertility was not back to normal levels, there was no noticeable difference in the litter size of females impregnated by the treated mice and no morphological defects were observed in any of the mice pups. There seemed to be no difference in the sperm that did make it through.</p>
<p>And Sun and his colleagues found that, unlike the gold nanorods that stayed indefinitely in mouse testicles, the iron nanorods were gradually eliminated into the liver and spleen, and later fully eliminated from the body. This reduced the risk for long-term toxicity.</p>
<h2>Controlled breeding</h2>
<p>The cost and the irreversibility of surgical castration <a href="https://doi.org/10.1177/1098612X15594994">lead many pet owners to look for alternative methods of contraception</a>. Nanocontraception is ready to be used on household pets, says Sun, and adds that this method is already being used on cats in China. </p>
<p>Surgical castration is less popular in Europe than in North America, so nanocontraception might be of greater interest there, says David Powell, director of the Reproductive Management Center of the Association of Zoos and Aquariums in St. Louis, Mo. “There’s really not a big pet contraception market in the U.S.,” says Powell.</p>
<p>He adds that contraception is not typically used with agricultural animals like sheep and cows. “They are reared for consumption and slaughter, so the agriculture industry is not doing much, if any, research on animal contraception.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A male lion and a cub" src="https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Viable contraception for animals can be a valuable tool for animal conservation and breeding programs.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>“Zoos are a very small market, and so drug companies don’t have a lot of motivation to make animal contraceptives,” says Powell. But some of them do, and the <a href="https://www.aza.org/reproductive-management-center/">Reproductive Management Center</a> collects data to evaluate how contraceptives work on different species.</p>
<p>Nanocontraception could be a part of zoos’ reproductive toolkit one day. But before this happens, says Powell, further studies would need to establish how painful it is and in which species the iron nanorods can be used. Research has indicated that some mammals — such as rhinoceroses, lemurs and dolphins — might accumulate iron, <a href="https://doi.org/10.1638/2011-0152.1">which can be toxic in larger quantities</a>.</p>
<h2>Reversible options</h2>
<p>One potential advantage of nanocontraception is its reversibility, as zoos often try to precisely time breeding events over animals’ life cycles. But just how reversible it is needs further study. All of Sun’s experiments treated mice only once; they were never subjected to a second injection of nanoparticles after their testicles had healed.</p>
<p>Sun’s ultimate goal is human contraception, although he admits that’s still a long way off. As with zoo animals, detailed studies will be required to establish that nanocontraception is not toxic for men. It is also more difficult to put a man under anesthesia for four hours and wrap an electric coil around his testicles than it is to do the same thing on a mouse. Instead, Sun hopes to be able to deliver the magnetic nanorods orally and find another way to direct them to the testicles.</p>
<p>And it is uncertain how many men will be comfortable with shrunken testicles, even if they recover their original size with time. </p>
<p>Until then, better get those condoms out.</p><img src="https://counter.theconversation.com/content/173979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeffrey Mo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Growing applications of nanotechnology include using nanorods for male birth control. The technique has had some success in animals, and offers the potential of human male contraception.Jeffrey Mo, Global Journalism Fellow, Dalla Lana School of Public Health, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1614142021-05-25T09:08:14Z2021-05-25T09:08:14ZVictoria’s egg and sperm bank will reduce the risks of seeking donors online. Here’s why it’s needed<figure><img src="https://images.theconversation.com/files/402535/original/file-20210525-24-1m0spj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/serious-confused-couple-checking-high-domestic-1156208635">Shutterstock</a></span></figcaption></figure><p>The <a href="https://www.premier.vic.gov.au/sites/default/files/2021-05/210512%20-%20Public%20IVF%20To%20Make%20Starting%20A%20Family%20Easier%20For%20Victorians.pdf">Victorian government’s budget announcement</a> to fund a public egg and sperm bank will be welcomed by couples and single women who need donors to conceive. </p>
<p>The bank will proactively recruit local donors, store donated eggs, sperm and embryos, and develop and deliver education and awareness programs about the need for donations. It will be the first of its kind in Australia, though it is not yet known when it will launch.</p>
<p>At a time when access to sperm and eggs are limited by low supply and high cost, a public donor bank will reduce the number of Victorians turning to potentially risky practices such as informal online donating or reproductive tourism overseas. </p>
<p>If it’s successful, other states and territories experiencing shortages may well follow. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meet-the-men-who-donate-sperm-on-facebook-104754">Meet the men who donate sperm on Facebook</a>
</strong>
</em>
</p>
<hr>
<h2>Shortages and high costs</h2>
<p>Victorians who need donated sperm and eggs are often faced with limited choice, lengthy wait lists created by <a href="https://s3.ap-southeast-2.amazonaws.com/hdp.au.prod.app.vic-engage.files/9915/6349/1942/ART_review_final_report_2.pdf">donor shortages</a>, and high costs. </p>
<p>When an egg donor is needed, recipients are largely left to their own devices, with most recruiting donors via online platforms. </p>
<p>IVF clinics typically have a greater supply of sperm donors, but <a href="https://s3.ap-southeast-2.amazonaws.com/hdp.au.prod.app.vic-engage.files/9915/6349/1942/ART_review_final_report_2.pdf">wait lists are still common and choices limited</a>. Victorian clinics report COVID-19 has exacerbated the problem, with <a href="https://www.theage.com.au/national/victoria/sperm-drought-fuels-unregulated-online-market-and-sex-assault-concerns-20210521-p57u0s.html">one reporting</a> a 90% drop in sperm donor inquiries during the pandemic.</p>
<p>The number of men donating sperm to Victorian clinics has actually <em><a href="https://www.varta.org.au/resources/annual-reports">increased</a></em> over the past decade. But demand has also increased, particularly since 2008 when it became legal for single and lesbian women to access fertility treatment in Victoria. </p>
<p>By <a href="https://www.varta.org.au/resources/annual-reports">2019/2020</a>, single women had become the largest group of women treated with donor sperm in Victoria (54%), followed by women in same-sex relationships (32%). </p>
<figure class="align-center ">
<img alt="Lesbian couple with two young children in the kitchen." src="https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/402533/original/file-20210525-15-1m9b847.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Demand for donor sperm has increased.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/girl-uses-tablet-kitchen-mum-other-411211480">Shutterstock</a></span>
</figcaption>
</figure>
<p>Despite the demand for donated sperm and eggs, private fertility clinics have not been successful in recruiting enough donors. </p>
<p>The other significant barrier to accessing donated eggs is cost. The cost of IVF can reach as much as <a href="https://www.genea.com.au/costs">A$10,000</a> for the first cycle. While clinics can’t charge for eggs, harvesting the eggs is a major cost of the process. If you eliminate that cost, the price of IVF drops dramatically. While a number of bulk-billing IVF clinics have opened in recent years, none provide donated eggs as part of their services. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/standard-ivf-is-fine-for-most-people-so-why-are-so-many-offered-an-expensive-sperm-injection-they-dont-need-158227">Standard IVF is fine for most people. So why are so many offered an expensive sperm injection they don't need?</a>
</strong>
</em>
</p>
<hr>
<h2>What are the risks of alternative methods?</h2>
<p>In recent years, and perhaps accelerated by the closure of Australia’s borders due to <a href="https://www.theage.com.au/national/victoria/sperm-drought-fuels-unregulated-online-market-and-sex-assault-concerns-20210521-p57u0s.html">COVID-19</a>, there has been an increase in unregulated sperm donation through online platforms where men offer their sperm to prospective parents. </p>
<p>This carries health risks because donor aren’t screened for sexually transmitted diseases. Sperm donated to clinics is quarantined for six months and then donors are re-screened for HIV, Hepatitis B and C,and syphilis prior to release for treatment. </p>
<p>There have also been <a href="https://www.theage.com.au/national/victoria/no-register-for-private-sperm-donors-after-victorian-government-rejects-suggestion-20210524-p57unh.html">reports</a> of women being pressured by donors to engage in “natural insemination” and even allegations of sexual assault. </p>
<figure class="align-center ">
<img alt="Lab technician performs IVF." src="https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/402536/original/file-20210525-19-1d4o25z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The cost of IVF in Australia can reach A$10,000 for the first cycle.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/technician-blue-gloves-does-control-check-626843126">Shutterstock</a></span>
</figcaption>
</figure>
<p>While fertility clinics are required by law to limit the number of children born from a single donor, <a href="https://www.news.com.au/lifestyle/real-life/news-life/brisbane-sperm-donor-investigated-after-fathering-23-kids-in-one-year/news-story/dfb0c65c7477a4b9bdaea9fc773928e9">offspring limits</a> cannot be controlled for in the informal market. Offspring limits reduce the risk of accidental incest. </p>
<p>Another issue is donor-conceived children may not have access to their donor’s identity. Clinic donors must agree to have their information on Victoria’s <a href="https://www.varta.org.au/donor-conception-register-services">Central Register</a> so their donor offspring have access to their identity. </p>
<p>But it’s impossible to ensure informal donors are registered, or to register the anonymous donors of children <a href="https://pubmed.ncbi.nlm.nih.gov/21269882/">conceived overseas</a> where eggs and sperm are more readily available. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/secrets-and-lies-why-donor-conceived-children-need-to-know-their-origins-44015">Secrets and lies: why donor-conceived children need to know their origins</a>
</strong>
</em>
</p>
<hr>
<h2>How might a public donor egg and sperm bank help?</h2>
<p>A public donor egg and sperm bank would focus on recruiting new sperm and egg donors, providing a greater number and range of donor eggs and sperm, at a lower cost. </p>
<p>Importantly, it would reduce reliance on risky informal sperm and egg donation arrangements and reproductive tourism to jurisdictions that provide fewer protections for children. </p>
<p>According to a Deloitte Access Economics <a href="https://s3.ap-southeast-2.amazonaws.com/hdp.au.prod.app.vic-engage.files/9915/6349/1942/ART_review_final_report_2.pdf">feasibility study</a>, for a public donor egg and sperm bank to deliver on its potential benefits, it <a href="https://www2.health.vic.gov.au/hospitals-and-health-services/patient-care/perinatal-reproductive/assisted-reproduction/regulatory-review">would need to</a> “orchestrate a social marketing campaign that speaks to the value of donation and seeks to influence social views on donation”.</p>
<p>Successful campaigns in other areas, such as blood, plasma and
breastmilk donation, have demonstrated that while changing community attitudes can take time, such campaigns can yield positive results.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/breast-milk-banking-continues-an-ancient-human-tradition-and-can-save-lives-69351">Breast milk banking continues an ancient human tradition and can save lives</a>
</strong>
</em>
</p>
<hr>
<p>Creating a <a href="https://pubmed.ncbi.nlm.nih.gov/12477959/">positive donor experience</a>, emphasising the importance of altruistic donation, the introduction of structural changes such as out-of-hours services, and the provision of adequate resources to support a sophisticated recruitment campaign, will be essential to the bank’s success.</p><img src="https://counter.theconversation.com/content/161414/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fiona Kelly received funding from the Australian Research Council to explore donor conception in Australia. She is also a member of the Board of the Victorian Assisted Reproductive Treatment Authority.</span></em></p>Victorians who need donated eggs and sperm face limited choice, lengthy waits and high costs.Fiona Kelly, Professor, Law School, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1600072021-05-03T20:08:22Z2021-05-03T20:08:22ZAre chemicals shrinking your penis and depleting your sperm? Here’s what the evidence really says<figure><img src="https://images.theconversation.com/files/398259/original/file-20210503-13-ocd03y.jpg?ixlib=rb-1.1.0&rect=14%2C0%2C4977%2C3323&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>A doomsday scenario of an end to human sperm production has been <a href="https://www.theguardian.com/commentisfree/2021/mar/18/toxic-chemicals-health-humanity-erin-brokovich">back in the news recently</a>, now with the added threat of shrinking penises.</p>
<p>Professor Shanna Swan, a US epidemiologist who studies environmental influences on human development, recently published a <a href="https://www.shannaswan.com/countdown">new book</a> called Countdown.</p>
<p>In it, she suggests sperm counts <a href="https://www.theguardian.com/society/2021/mar/28/shanna-swan-fertility-reproduction-count-down">could reach zero by 2045</a>, largely owing to the impact of a range of environmental pollutants used in manufacturing everyday products: phthalates and bisphosphenol A (BPA) from plastics, and per- and poly-fluoroalkyl substances (PFAS) used, for example, in waterproofing. Under this scenario, she says, most couples wanting to conceive would need to rely on assisted reproductive technologies.</p>
<p>She has also warned these chemicals are shrinking penis size.</p>
<p>Such extraordinary claims require extraordinary evidence. I would argue the evidence is not strong enough.</p>
<h2>Correlation doesn’t equal causation</h2>
<p>Epidemiologists find associations between disease and potential contributing factors, like lung cancer and smoking. But their work can’t identify the causes of disease — just because two things are associated doesn’t mean one is causing, or caused by, the other.</p>
<p>An article written by environmental activist Erin Brockovich in <a href="https://www.theguardian.com/commentisfree/2021/mar/18/toxic-chemicals-health-humanity-erin-brokovich">The Guardian</a> in March leads by referring to “hormone-disrupting chemicals that are decimating fertility”. But causation is <a href="https://pubmed.ncbi.nlm.nih.gov/33385395/">far from established</a>. </p>
<p>It’s reasonable to expect chemicals that <a href="https://pubmed.ncbi.nlm.nih.gov/33385395/">affect hormone function</a> in our bodies, like BPA and PFAS, could affect reproduction in males and females, given available evidence. But we don’t have irrefutable proof.</p>
<figure class="align-center ">
<img alt="A man and a pregnant woman outside with their dog." src="https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398265/original/file-20210503-17-fzbt4d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Could environmental pollutants be leading to infertility? Establishing cause and effect isn’t clear-cut.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Selective reporting</h2>
<p>In 2017, Swan and several colleagues published <a href="https://pubmed.ncbi.nlm.nih.gov/28981654/">an exhaustive review study</a> showing an apparent drop in men’s sperm counts of 59.3% between 1973 and 2011. This research informs the arguments Swan makes in Countdown and those we’ve seen in the media.</p>
<p>What’s not often mentioned is the fact the researchers only observed a decline in sperm count in groups of men from North America, Europe, Australia, and New Zealand, but not in groups of men from South America, Asia or Africa.</p>
<p>When Swan and her colleagues combined the data from all countries, they saw a decline because the studies of “Western” men outweigh those of men elsewhere (in the number of studies and participants).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/huge-drop-in-mens-sperm-levels-confirmed-by-new-study-here-are-the-facts-81582">Huge drop in men's sperm levels confirmed by new study – here are the facts</a>
</strong>
</em>
</p>
<hr>
<p>Swan and her colleagues worked hard to avoid bias when conducting their study. But <a href="https://pubmed.ncbi.nlm.nih.gov/9455838/">selection bias</a> (related to how study participants are chosen), <a href="https://pubmed.ncbi.nlm.nih.gov/2406472/">publication bias</a> (resulting from researchers’ tendency to report only observations they think will be of interest) and other limitations of the original work used as the basis for their investigation could be influencing the results of the larger study.</p>
<p>Many studies from different parts of the world show declining sperm counts, which is concerning, but we don’t fully understand the <a href="https://pubmed.ncbi.nlm.nih.gov/32168194/">reasons for the apparent decline</a>. Blaming chemicals in the environment overlooks <a href="https://pubmed.ncbi.nlm.nih.gov/29774489/">other important factors</a> such as chronic disease, diet, and obesity, which people can act on to improve their fertility.</p>
<h2>The problem with extrapolation</h2>
<p>Swan’s 2017 study boils down to a straight descending line drawn between sperm counts of groups of men studied at different times between 1973 and 2011.</p>
<p>Just because a straight line can be drawn through the data, this doesn’t justify extrapolation of that line beyond its earliest and latest data points. It’s unscientific to assume trends in data exist outside the range of observations.</p>
<p>We know sperm counts of men in the early 1940s were around <a href="https://pubmed.ncbi.nlm.nih.gov/1393072/">113 million sperm per ml of semen</a>, not the roughly 140 million/ml you get from extrapolating backwards from Swan’s research. Concluding sperm counts will reach zero in 2045, based on extrapolating forward from the available data, is just as likely to be incorrect. </p>
<p>When Swan told <a href="https://www.axios.com/newsletters/axios-future-e58ada65-1a84-4550-afd8-79d698bb7d38.html?stream=future&utm_campaign=newsletter_axiosfutureofwork&utm_medium=email&utm_source=newsletter">news website Axios</a> “If you look at the curve on sperm count and project it forward” she was encouraging unjustifiable and unscientific interpretation of her data — even though she acknowledged it was “risky” to extrapolate in this way. Unfortunately this caution is too often unmentioned.</p>
<p>For example, <a href="https://www.theguardian.com/commentisfree/2021/mar/18/toxic-chemicals-health-humanity-erin-brokovich">Brockovich writes</a>: “That would mean no babies. No reproduction. No more humans.” That’s hyperbole. It’s just not science.</p>
<figure class="align-center ">
<img alt="An illustration of sperm." src="https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398266/original/file-20210503-23-8j0tma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Swan has extrapolated from recent data to predict sperm counts could reach zero by 2045. But this isn’t necessarily accurate.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Relax, your penis isn’t shrinking</h2>
<p>Claims of shrinking penises are obvious clickbait. But only <a href="https://pubmed.ncbi.nlm.nih.gov/30403786/">a single study</a>, of 383 young men from the Veneto region in northeastern Italy, links men’s penis size to the types of chemicals Swan attributes to declining sperm counts.</p>
<p>Within Veneto there are <a href="https://figshare.com/articles/figure/Supplemental_Figure_1/7016234">geographic zones</a> with varied levels of PFAS contamination. A group of 212 men who live in areas with high or intermediate PFAS exposure and have high levels of these chemicals in their bodies, had an average penis length of 8.6cm, about 10% lower than the average of a group of 171 men from an area without exposure (9.7cm).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/science-or-snake-oil-do-men-need-sperm-health-supplements-84379">Science or Snake Oil: do men need sperm health supplements?</a>
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<p>But a few features of this study affect the reliability of the observations and whether we can generalise them to other populations.</p>
<ol>
<li><p>men were grouped according to where they lived, not where they were born. Since genital size is <a href="https://pubmed.ncbi.nlm.nih.gov/30403786/">determined before birth</a>, the environment during their mothers’ pregnancies is more relevant to penis size than where the men lived at the time of the study. Some men will likely have relocated from their place of birth but how many, and where they may have moved to and from, we don’t know</p></li>
<li><p>the levels of PFAS exposure for men living in the contaminated regions of Veneto are extreme, because of <a href="https://pubmed.ncbi.nlm.nih.gov/29108835/">decades of industrial pollution</a>. How the potential effect of such large exposures relates to smaller and more common exposures to pollutants, like from plastic food wrap, we don’t know</p></li>
<li><p>the study is missing details about its subjects and the conditions under which measurements were made. It’s <a href="https://pubmed.ncbi.nlm.nih.gov/33748967/">usual</a> to exclude people with conditions that might affect study outcomes, such as congenital abnormalities, but it’s not clear whether this happened in the study. Variables that <a href="https://pubmed.ncbi.nlm.nih.gov/31171853/">influence penile measurements</a> (such as room temperature, posture, and whether the penis is held straight or hanging) are not mentioned.</p></li>
</ol>
<p>And from a semantic perspective, for penises to be “shrinking” they must be getting shorter over time, on either an individual or population basis. I cannot find any reports of men’s penises shortening as a consequence of environmental pollution. <a href="https://pubmed.ncbi.nlm.nih.gov/31171853/">Available data</a> <a href="https://pubmed.ncbi.nlm.nih.gov/25487360/">don’t suggest</a> a decline in penis size over the past few decades.</p>
<p>While environmental pollution is a pressing concern, the evidence suggests the catastrophic collapse of human reproduction and accompanying penis shrinkage is thankfully a pretty unlikely prospect.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/considering-using-ivf-to-have-a-baby-heres-what-you-need-to-know-108910">Considering using IVF to have a baby? Here's what you need to know</a>
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</p>
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<img src="https://counter.theconversation.com/content/160007/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Moss is Health Content Manager at Healthy Male (formerly Andrology Australia). He is the current President of The Perinatal Society of Australia and New Zealand. </span></em></p>Warnings of an end to human sperm production have been making headlines recently, now with the added threat of shrinking penises. Is this science or sensationalism?Tim Moss, Adjunct Associate Professor, Department of Obstetrics and Gynaecology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1582272021-04-22T22:40:53Z2021-04-22T22:40:53ZStandard IVF is fine for most people. So why are so many offered an expensive sperm injection they don’t need?<figure><img src="https://images.theconversation.com/files/394939/original/file-20210414-13-10bvrbn.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C1000%2C727&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/intracytoplasmic-sperm-injection-icsi-part-ivf-1394225165">from www.shutterstock.com</a></span></figcaption></figure><p>An expensive IVF technique, routinely offered in fertility clinics around the world, offers no extra benefits to standard IVF in the vast majority of cases, our new research shows.</p>
<p>The technique, known as intracytoplasmic sperm injection or ICSI, was developed to help couples where the man has a low sperm count. But it is now the main fertilisation method clinics use in Australia and New Zealand, even when sperm counts are normal. </p>
<p>In an article published today in <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00535-3/fulltext">The Lancet</a> we show that when there’s a normal sperm count, ICSI does not improve the chance of a baby when compared with standard IVF. So why do clinics routinely offer it?</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/considering-using-ivf-to-have-a-baby-heres-what-you-need-to-know-108910">Considering using IVF to have a baby? Here's what you need to know</a>
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</p>
<hr>
<h2>What is ICSI?</h2>
<p>In IVF, several thousand sperm compete to be the one to fertilise an egg. However, for the small percentage of couples with what doctors call severe male-factor infertility — for instance, where there is a very low sperm count or the sperm doesn’t look or move normally — IVF is not an option. </p>
<p>In 1992, ICSI <a href="https://pubmed.ncbi.nlm.nih.gov/1351601/">was introduced</a>, where a single sperm was injected into the egg using a glass needle. This allowed the expansion of IVF to people where low sperm counts or poor sperm quality was an issue.</p>
<p>Its introduction across the world has helped thousands of couples have biologically related children, who otherwise would have needed donor sperm or remained childless.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="IVF versus ICSI" src="https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/396213/original/file-20210421-19-1aj9ka7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">With IVF, thousands of sperm compete to fertilise an egg. But with ICSI, a single sperm is injected into the egg.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/types-artificial-fertilization-egg-spermotozoydami-plant-1437755195">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<h2>How common is it?</h2>
<p>ICSI was expected to be used only where male infertility was an issue, but over time it has become the most used method of fertilisation even when it isn’t.</p>
<p>In the United States, between 1996 and 2012, ICSI use <a href="https://jamanetwork.com/journals/jama/fullarticle/2091303">increased</a> from 15% to 67% of couples where the male has a normal sperm count; in Europe about <a href="https://pubmed.ncbi.nlm.nih.gov/30032255/">70% of cycles</a> use ICSI.</p>
<p>In <a href="https://npesu.unsw.edu.au/sites/default/files/npesu/data_collection/Assisted%20Reproductive%20Technology%20in%20Australia%20and%20New%20Zealand%202018_0.pdf">Australia</a> around 60% of cycles used ICSI in 2018. This is even though <a href="https://www.auanet.org/guidelines/azoospermic-male-best-practice-statement">only</a> 30% of infertile couples have male infertility and 15% severe male infertility.</p>
<p>Clinics in Australia use ICSI to different extents. For instance, in Victoria in 2019-20, ICSI was used between <a href="https://www.varta.org.au/sites/default/files/2021-01/varta-annual-report-2020.pdf.pdf">34% and 89%</a> of the time, depending on the clinic.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sperm-why-these-secretive-swimmers-are-the-key-to-the-future-of-fertility-and-contraception-81773">Sperm: why these secretive swimmers are the key to the future of fertility – and contraception</a>
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</em>
</p>
<hr>
<h2>What we did and what we found</h2>
<p>Today we report, with our collaborators in Vietnam, the results of a large study in which more than 1,000 infertile couples with a normal sperm count were randomly allocated to ICSI or IVF. We found couples in either group were just as likely to have a baby.</p>
<p>This adds to evidence from other <a href="https://pubmed.ncbi.nlm.nih.gov/29897449/#:%7E:text=What%20is%20known%20already%3A%20The,with%20non%2Dmale%20factor%20infertility">large observational studies</a> in as many as 15,000 women that the widespread use of the more expensive and technically demanding ICSI does not offer any benefit to couples where the man has a normal sperm count. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/32896391/">Excellent clinics</a> internationally and in Australia perform ICSI in fewer than 35% of their treatments, while achieving success rates equal to or better than clinics using ICSI more commonly.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fertility-miracle-or-fake-news-understanding-which-ivf-add-ons-really-work-118585">Fertility miracle or fake news? Understanding which IVF 'add-ons' really work</a>
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<hr>
<h2>How did ICSI become so popular?</h2>
<p>There are a <a href="https://www.hfea.gov.uk/treatments/treatment-add-ons/">growing number</a> of fertility treatments that <a href="https://www.fertstert.org/article/S0015-0282(19)32454-9/fulltext">aren’t backed by reasonable evidence</a>. </p>
<p>Some are relatively cheap, such as vitamins and antioxidants. Others are invasive or expensive. These include <a href="https://www.hfea.gov.uk/treatments/treatment-add-ons/endometrial-scratching/">endometrial scratching</a> (where the lining of the uterus is scraped with a thin tube, which is said to improve the chance of an embryo implanting), video microscopy of embryos, and <a href="https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2020/03/preimplantation-genetic-testing">pre-implantation genetic diagnosis</a> for potential chromosome abnormalities (where an embryo is tested for genetic disease before being implanted).</p>
<p>In fact, ICSI is about A$500 more expensive than standard IVF, although costs vary between clinics, and some costs can be claimed on <a href="http://www9.health.gov.au/mbs/fullDisplay.cfm?type=item&q=13218&qt=item">Medicare</a> under specific circumstances.</p>
<p>So why are these so-called “add-ons” or “adjuvants” so common?</p>
<p>Fertility treatment, especially IVF and ICSI, is overwhelmingly practised in the private sector in Australia and New Zealand. It is strongly marketed to the public and promoted in social media by individual doctors, clinics and corporations. Doctors and clinics also compete for patients, often offering <a href="https://theconversation.com/fertility-miracle-or-fake-news-understanding-which-ivf-add-ons-really-work-118585">unproven therapies</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-business-of-ivf-how-human-eggs-went-from-simple-cells-to-a-valuable-commodity-119168">The business of IVF: how human eggs went from simple cells to a valuable commodity</a>
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<p>Couples may overlook a doctor seeking to practise fertility medicine based solely on evidence, and instead find a nearby clinic or doctor <a href="https://obgyn.onlinelibrary.wiley.com/doi/abs/10.1111/ajo.13321">prepared to offer</a> add-ons they believe will improve their chance of a baby.</p>
<p>In the case of ICSI, doctors may recommend it for fear of patients’ reactions if the eggs don’t fertilise, even if ICSI doesn’t improve the ultimate chance of a baby for those with a normal sperm count.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1191669372747538439"}"></div></p>
<h2>What can we do about it?</h2>
<p>Infertility is distressing and, in most cases, can be easily treated with good advice, simple drugs and, if needed, quality assisted reproductive procedures such as IVF.</p>
<p>However, unrestrained, unnecessary use of ICSI is a salutary example of why we need to act on widely accepted evidence.</p>
<p>Until now, the fertility industry has promoted <a href="https://www.abc.net.au/radio/programs/pm/ivf-specialists-hit-back-at-four-corners-story-on/7464870">self-regulation</a> over being made to follow government-imposed, evidence-based guidelines of which fertility treatments are needed. And there’s a <a href="https://www.fertstert.org/article/S0015-0282(19)32454-9/fulltext">growing concern</a> the industry is not doing enough to combat unproven and expensive treatments.</p>
<p>Couples with infertility belong to a <a href="https://pubmed.ncbi.nlm.nih.gov/18025030/">very vulnerable group</a> who will do almost anything to achieve a pregnancy. They deserve our dedicated care and evidence-based treatment.</p><img src="https://counter.theconversation.com/content/158227/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Norman is not involved financially in any IVF or fertility clinic </span></em></p><p class="fine-print"><em><span>Ben W. Mol receives funding from NHMRC (Investigatorgrant GNT1176437) Guerbet, and Ferring.
</span></em></p>Our new study shows a widely used fertility treatment, known as ICSI, is no better than standard IVF for most people. Yet, it’s being routinely offered around the world.Robert Norman, Professor of Reproductive and Periconceptual Medicine, The Robinson Institute, University of AdelaideBen W. Mol, Professor of Obstetrics and Gynaecology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1580972021-04-14T14:26:21Z2021-04-14T14:26:21ZMale fertility: how everyday chemicals are destroying sperm counts in humans and animals<figure><img src="https://images.theconversation.com/files/395221/original/file-20210415-21-qpw45h.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C4992%2C2597&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/human-sperm-13949494">SciePro/Shutterstock</a></span></figcaption></figure><p>Within just a few generations, human sperm counts may decline to levels below those considered adequate for fertility. That’s the alarming claim made in epidemiologist Shanna Swan’s new book, “<a href="https://www.ehn.org/environmental-toxics-infertility-2650517682/the-drop-heard-round-the-world">Countdown</a>”, which assembles a raft of evidence to show that the sperm count of western men has plunged by over 50% in less than 40 years.</p>
<p>That means men reading this article will on average have half the sperm count of their grandfathers. And, if the data is extrapolated forwards to its logical conclusion, men could have little or no reproductive capacity from 2060 onwards.</p>
<p>These are shocking claims, but they’re backed by a growing body of evidence that’s finding reproductive abnormalities and declining fertility in humans and wildlife worldwide. </p>
<p>It’s difficult to say whether these trends will continue – or whether, if they do, they could lead to our <a href="https://www.nytimes.com/2021/03/05/books/review/shanna-swan-count-down.html">extinction</a>. But it’s clear that one of the main causes of these issues – the chemicals we’re surrounded by in our everyday lives – requires better regulation in order to protect our reproductive capacities, and those of the creatures with which we share our environment. </p>
<h2>Declining sperm count</h2>
<p>Studies revealing declining sperm counts in humans aren’t new. These issues first received global attention <a href="https://pubmed.ncbi.nlm.nih.gov/8212356/">in the 1990s</a>, though critics pointed to <a href="https://pubmed.ncbi.nlm.nih.gov/8612832/">discrepancies</a> in the way sperm counts were recorded to downplay the findings.</p>
<p>Then, in 2017, <a href="https://academic.oup.com/humupd/article/23/6/646/4035689">a more robust study</a> that accounted for these discrepancies revealed that the sperm count of western men had declined by 50%-60% between 1973 and 2011, dropping on average 1%-2% per year. This is the “countdown” to which Shanna Swan refers.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/huge-drop-in-mens-sperm-levels-confirmed-by-new-study-here-are-the-facts-81582">Huge drop in men's sperm levels confirmed by new study – here are the facts</a>
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<p>The lower a man’s sperm count, the lower their chance of conceiving a child through sexual intercourse. The 2017 study warns that our grandchildren could possess sperm counts below the level considered suitable for successful conception – likely to force “<a href="https://www.theguardian.com/society/2021/mar/28/shanna-swan-fertility-reproduction-count-down">most couples</a>” to use assisted reproduction methods by 2045, according to Swan. </p>
<figure class="align-center ">
<img alt="Shanna Swan speaking in an interview" src="https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395000/original/file-20210414-19-vao4ty.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Reproductive epidemiologist Shanna Swan believes falling sperm counts are ‘imperilling the future of the human race’.</span>
<span class="attribution"><a class="source" href="https://trikooba.com/wp-content/uploads/2021/03/Shanna-Swan-750x375.jpg">Trikooba</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Equally alarming is an <a href="https://academic.oup.com/edrv/article/30/4/293/2355049?login=true">increase</a> in the rate of miscarriages and developmental abnormalities in humans, such as small penis development, intersexuality (displaying both male and female characteristics) and non-descended testes – all <a href="https://www.sciencedirect.com/science/article/abs/pii/S0303720711006824">found to be linked</a> to declining sperm count.</p>
<h2>Why fertility is falling</h2>
<p>Many factors could explain these trends. After all, lifestyles have changed dramatically since 1973, including changes in diet, exercise, obesity levels and alcohol intake – all of which we know can contribute to low sperm counts. </p>
<p>But in recent years, researchers have pinpointed the <a href="https://www.embopress.org/doi/full/10.1038/embor.2012.50">foetal stage</a> of human development, before any lifestyle factors come into play, as a decisive moment for men’s reproductive health. </p>
<p>During the “<a href="https://pubmed.ncbi.nlm.nih.gov/18340380/">programming window</a>” for foetal masculinisation – when the foetus develops male characteristics – disruptions in hormone signalling have been shown to have a lasting impact on male reproductive capabilites into adulthood. This was originally proven in animal studies, but there’s now growing support from <a href="https://pubmed.ncbi.nlm.nih.gov/28352662/">human studies</a>.</p>
<p>This hormonal interference is caused <a href="https://www.who.int/ceh/publications/endocrine/en/">by chemicals</a> in our everyday products, which have the capacity to either act like our hormones, or to prevent them from functioning properly at key stages in our development.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/exposure-to-toxic-chemicals-in-everyday-products-could-affect-expectant-mothers-30423">Exposure to toxic chemicals in everyday products could affect expectant mothers</a>
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<p>We call these “<a href="https://www.endocrine.org/topics/edc">endocrine-disrupting chemicals</a>” (EDCs), and we’re exposed to them through what we eat and drink, the air we breathe, and the products we put on our skin. They’re sometimes called “<a href="https://www.ehn.org/fertility-crisis-2650749642/phthalates-the-everywhere-chemical">everywhere chemicals</a>”, because they’re very difficult to avoid in the modern world. </p>
<h2>Exposure to EDCs</h2>
<p>EDCs are passed to the foetus by the mother, whose <a href="https://pubmed.ncbi.nlm.nih.gov/33728432/">exposure to the chemicals</a> during her pregnancy will determine the degree to which the foetus experiences hormonal interference. That means that present-day sperm count data speaks not to the chemical environment today, but to the environment as it was when those men were still in the womb. That environment is undoubtedly becoming more polluted.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2726844/">It’s not just one</a> specific chemical causing the disruption. Different types of everyday chemical – found in everything from washing up liquids to pesticides, additives and plastics – can all disrupt the normal functioning of our hormones. </p>
<p>Some, like those in the <a href="https://www.sciencedirect.com/science/article/pii/S0166445X03001772">contraceptive pill</a>, or those used as <a href="https://www.sciencedirect.com/science/article/pii/S0269749118327131">growth promoters</a> in animal farming, were specifically designed to affect hormones, but are now found throughout the environment.</p>
<figure class="align-center ">
<img alt="Some pills in their packaging" src="https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395032/original/file-20210414-13-a40pql.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The chemicals in the contraceptive pill eventually find their way into the water we drink.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tablets-standards-various-shapes-colors-copy-1933809071">Vectorina/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Are animals suffering too?</h2>
<p>If chemicals are to blame for declining sperm counts in humans, you’d expect the animals that share our chemical environments to be affected too. And so they are: a recent study found that <a href="https://www.nature.com/articles/s41598-021-86805-y">pet dogs</a> are suffering the same decline in sperm counts for the same reasons as we are.</p>
<p>Studies of farmed mink in <a href="https://pubmed.ncbi.nlm.nih.gov/9924010/">Canada</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0045653514008595">Sweden</a>, meanwhile, have also linked industrial and agricultural chemicals with the creatures’ lower sperm counts and abnormal testicular and penis development. </p>
<p>In the wider environment, the effect has been seen in <a href="https://academic.oup.com/icb/article/40/3/438/379945?login=true">alligators</a> in Florida, in <a href="https://www.sciencedirect.com/science/article/pii/S0166445X21000527?via%3Dihub">shrimp-like crustaceans</a> in the UK, and in <a href="https://pubs.acs.org/doi/abs/10.1021/es9710870">fish</a> living downstream of wastewater treatment plants around the world.</p>
<p>Even species thought to roam far away from these sources of pollution are suffering from chemical contamination. A female killer whale that washed up on the shores of Scotland in 2017 was found to be one of the <a href="https://www.bbc.co.uk/news/science-environment-39738582">most contaminated biological specimens</a> ever reported. Scientists say she never calved.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-effect-on-sperm-could-hold-key-to-species-extinction-107375">Climate change: effect on sperm could hold key to species extinction</a>
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</em>
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<h2>Regulating chemicals</h2>
<p>In some instances, the abnormalities observed in wildlife are linked with very different chemical compounds to those observed in humans. But they all share a capacity to disrupt the normal functioning of the hormones that dictate reproductive health.</p>
<p>In the UK, the Department for Environment, Food and Rural Affairs is currently building a <a href="https://www.icis.com/explore/resources/news/2020/01/29/10461868/uk-government-to-develop-new-chemicals-strategy">chemicals strategy</a> that could address these issues. <a href="https://ec.europa.eu/growth/sectors/chemicals/legislation_en">The EU</a>, meanwhile, is changing chemical regulations to prevent banned substances being replaced with other harmful ones.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/do-we-really-face-a-human-fertility-cliff-edge-science-offers-hope-82022">Do we really face a human fertility cliff-edge? Science offers hope</a>
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<p>Ultimately, public pressure could demand stronger regulatory interventions, but as chemicals are invisible – less tangible than plastic straws and smoking chimneys – this may prove difficult to achieve. Shanna Swan’s book, which presents the urgency of our reproductive situation, is certainly an important contribution to this end.</p><img src="https://counter.theconversation.com/content/158097/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alex Ford receives funding from the Natural Environment Research Council (NERC) UK and European Union Interreg program. He is the Deputy Director of the Centre of Blue Governance at the University of Portsmouth and long serving member for the Society of Environmental Toxicology and Chemistry (SETAC) </span></em></p><p class="fine-print"><em><span>Gary Hutchison receives funding from European Union Horizon 2020. He is an independent scientific advisor with membership of UK Hazardous Substances Advisory Committee, DEFRA, and the FSA Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment. He is a member of a number of specialist registers from the FSA, Defra and the Office for Product Safety & Standards. He is a member of the British Toxicology Society, Scottish Government Chemical Policy Network and UK Parliamentary and Scientific Committee.</span></em></p>Our chemical environment appears responsible for an alarming plummet in sperm counts – in humans and in animals.Alex Ford, Professor of Biology, University of PortsmouthGary Hutchison, Professor of Toxicology and Dean of Applied Sciences, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1558072021-03-16T12:10:31Z2021-03-16T12:10:31ZSperm from older rats passes on fewer active genes to offspring because of epigenetic changes<figure><img src="https://images.theconversation.com/files/387892/original/file-20210304-21-1sdlsl8.jpg?ixlib=rb-1.1.0&rect=0%2C10%2C3500%2C2315&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If the same mechanism exists in humans, it may explain health differences in children conceived by older fathers.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/laboratory-rat-with-red-eyes-looks-out-of-plastic-royalty-free-image/155372897">fotografixx/E+ via Getty Images</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>The sperm of older rats differs from that of younger rats in ways that may affect embryo development, according to recently published research.</p>
<p>Sperm carries not only genes, but also instructions that determine which genes will be turned on or off in offspring. These directions are known as <a href="https://www.cdc.gov/genomics/disease/epigenetics.htm">epigenetic information</a>. </p>
<p>In the rats we studied, age had a profound effect on the activity of many genes in sperm. We found age affected two epigenetic mechanisms in particular: <a href="https://doi.org/10.2217/epi-2020-0404">DNA methylation</a>, which chemically alters DNA to block specific genes, and <a href="https://doi.org/10.3390/ijms21218252">small RNA</a>, another method of gene silencing.</p>
<h2>Why it matters</h2>
<p>In developed countries, people are having their first child later than ever before. In the U.S., the number of men between the ages of 35 and 44 fathering children <a href="https://europepmc.org/article/med/24974589">increased 50% over the past three decades</a>. A downside of this trend is that children conceived by older fathers have a higher risk of adverse health conditions.</p>
<p>These conditions include different forms of <a href="https://doi.org/10.1093/ije/30.6.1428">cancer</a>, <a href="https://doi.org/10.1001/archpsyc.58.4.361">schizophrenia</a>, <a href="https://doi.org/10.1038/mp.2010.121">autism spectrum disorder</a>, <a href="https://doi.org/10.1001/archpsyc.65.9.1034">bipolar disorder</a> and <a href="https://doi.org/10.1001/jamapsychiatry.2013.4525">attention deficit/hyperactivity disorder</a>, among others. </p>
<p>It is now clear the quality of information transferred by sperm decreases with age. We still do not know, however, if these changes occur through an <a href="https://doi.org/10.3892/br.2019.1266">accumulation of mutations or some other mechanisms</a>. Our rat data suggests epigenetic changes are one culprit.</p>
<h2>How we do our work</h2>
<p>In our experiments, we collected sperm from 65-day-old rats and 120-day-old rats. These ages correspond approximately to 20-to 25- and 40- to 45-year-old humans. We analyzed the sperm of these animals using methods based on DNA sequencing and found the sperm of older rats had very different epigenetic profiles – or operating instructions – than younger rats did. </p>
<p>In older rats, 5,319 DNA sites had different levels of methylation, an epigenetic mechanism that occurs when <a href="https://doi.org/10.1038/s41580-019-0159-6">methyl group (-CH3) is added to DNA</a>. Because even <a href="https://doi.org/10.1186/s12864-018-5387-1">single instances of methylation may result in switching off nearby genes</a>, the number of sites we found is enough to affect 5% of all rat genes. </p>
<p>Older rat sperm also had different concentrations of small RNAs, which are a large class of tiny molecules that can interfere with the expression of genes. We found that 3.6% of all <a href="https://doi.org/10.3390/ijms21218252">identified small RNAs</a> were different in older rats. Like DNA methylation, changes in small RNA can affect the <a href="https://doi.org/10.3390/ijms17101712">activities of multiple genes</a>. </p>
<p>Using computational algorithms, we identified the genes affected by these epigenetic mechanisms – 3,066 were regulated by DNA methylation and 4,950 by small RNA, with <a href="https://doi.org/10.2217/epi-2020-0404">significant overlap</a>. Most of the genes we identified regulate embryonic development, including that of the brain and other organs.</p>
<p>Our study analyzed only sperm – it did not study offspring. But knowing which genes are likely to be turned off – and their specific functions – allows us to confidently predict what will go wrong in the development of rat pups fathered by older rats. If the same mechanism exists in humans, epigenetic changes in sperm may be partly responsible for the greater risk of certain health conditions in children conceived by older fathers. </p>
<h2>What still isn’t known</h2>
<p>Emerging research shows <a href="https://doi.org/10.1038/s41598-020-80857-2">similar age-related changes do occur in human sperm</a>. But the epigenetic study of human sperm is in its infancy. Unlike genetic information, which is fixed, epigenetic information is highly flexible and can be <a href="https://doi.org/10.1111/andr.12753">altered by many lifestyle and environmental factors</a>. My colleagues and I hope our research will help to develop future therapies that can address the health of children before they are even conceived.</p>
<p>[<em>Insight, in your inbox each day.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=insight">You can get it with The Conversation’s email newsletter</a>.]</p><img src="https://counter.theconversation.com/content/155807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Suvorov receives funding from US National Science Foundation, Russian Science Foundation
I have adjunct affiliation with the Institute of Physico-Chemical Biology of the Moscow State University, </span></em></p>Male rats transfer different hereditary information to their offspring depending on their age.Alexander Suvorov, Assistant Professor of Environmental Health Sciences, UMass AmherstLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1536362021-02-02T19:05:25Z2021-02-02T19:05:25ZDo you really need IVF? A new online tool can help you weigh up your options<figure><img src="https://images.theconversation.com/files/381840/original/file-20210202-19-s48ku2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6720%2C3780&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>People who want a baby and struggle to conceive often resort to in vitro fertilisation (IVF). While IVF has helped countless people have children, it’s expensive and comes with some risks. </p>
<p>But research shows some people with so-called “unexplained infertility” have a <a href="https://pubmed.ncbi.nlm.nih.gov/30358841/">30-40% chance</a> of conceiving without treatment if they just keep trying for a bit longer.</p>
<p>So, how long should you wait before starting fertility treatment? This depends on a range of factors that might increase or decrease your chance of conceiving naturally, as well as your personal preferences for seeking treatment or not. </p>
<p>A new <a href="https://www.yourfertility.org.au/general-resources/interactive-tools/unexplained-infertility">online guide</a> can estimate your chance of conceiving with and without treatment. The free tool collects information based on what we understand to be the main factors affecting a woman’s chance of falling pregnant, with a view to informing decisions around fertility treatment.</p>
<h2>Sometimes there’s no clear explanation</h2>
<p>It’s recommended women who have tried unsuccessfully for a baby for 12 months, or six months if they’re over 35, <a href="https://www1.racgp.org.au/ajgp/2020/june/female-fertility-in-general-practice-setting">seek medical advice</a>. This is so the doctor can arrange for tests to determine whether there’s a reason for infertility. </p>
<p>If these tests show the <a href="https://www.ncbi.nlm.nih.gov/books/NBK556033/">woman’s fallopian tubes are blocked</a>, or that the male partner has a <a href="https://academic.oup.com/humupd/article/23/6/660/3979420">very low sperm count</a>, it’s best to go straight to IVF. In most cases, that’s the only way the couple will be able to get pregnant.</p>
<p>If your doctor finds no obvious problem, you have what’s called “<a href="https://www.yourfertility.org.au/general-resources/interactive-tools/unexplained-infertility">unexplained</a>” or “idiopathic” infertility. </p>
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<img alt="A doctor talks to a couple." src="https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381844/original/file-20210202-23-16rlsxw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">It’s worth seeing a doctor if you’ve tried unsuccessfully to conceive for 12 months, or six months if you’re over 35.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Weighing up your options</h2>
<p>It can be very frustrating to be told there’s nothing wrong, when month after month goes by without pregnancy happening. </p>
<p>Although IVF might seem like the fastest option, it can be <a href="https://www.varta.org.au/resources/information-sheets/costs-ivf">expensive</a>, costing most people thousands of dollars. And like any medical procedure, <a href="https://www.varta.org.au/resources/information-sheets/possible-health-effects-ivf">IVF carries risks</a>, particularly for women. </p>
<p>If your tests come back normal, it might be worth considering giving nature a bit more time, or trying a simpler form of infertility treatment, such as <a href="https://www.varta.org.au/fertility-treatment/fertility-treatment-explained#Types-of-treatment">intrauterine insemination</a> (IUI). IUI involves insertion of the male partner’s (or a donor’s) sperm into a woman’s uterus at or just before ovulation.</p>
<p>So which path is right for you? This is where the new online guide can help.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-have-pcos-and-i-want-to-have-a-baby-what-do-i-need-to-know-109800">I have PCOS and I want to have a baby, what do I need to know?</a>
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<h2>It’s built on evidence</h2>
<p>Research tracking thousands of people with unexplained infertility has found many go on to have healthy babies <a href="https://pubmed.ncbi.nlm.nih.gov/30358841/">naturally</a>, or with the help of <a href="https://pubmed.ncbi.nlm.nih.gov/17408625/">simple fertility treatment</a>. In one study of more than 1,200 couples with unexplained infertility, <a href="https://pubmed.ncbi.nlm.nih.gov/30358841/">25% conceived naturally</a> within 12 months. </p>
<p>Of course, for some women conception will be more likely, and for some women it will be less likely.</p>
<p>Experts used the data from this research to develop the online guide. The personalised calculations are based on four factors that evidence indicates are most likely to affect the chance of pregnancy. </p>
<p>The most important factor that affects a woman’s <a href="https://www.yourfertility.org.au/everyone/age">chance of having a baby</a> — naturally or with IVF — is her age. So what’s labelled unexplained infertility may in fact be <a href="https://academic.oup.com/humrep/article/31/7/1390/1749660">age-related</a>. While pregnancy can still happen, by age 40 a woman’s fertility is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4893975/">about half</a> the level it was when she was 30.</p>
<p>Other factors include how long she has been <a href="https://www.bmj.com/content/327/7412/434">trying for a baby</a> (the likelihood of conception decreases with the duration of trying), whether she’s been <a href="https://www.fertstert.org/article/S0015-0282(16)00152-7/fulltext">pregnant before</a> (women who have never conceived before have a lower probability of achieving a pregnancy), and what proportion of the male partner’s sperm move normally (called “<a href="https://academic.oup.com/humrep/article/17/1/173/554152">progressive motility</a>” on a semen analysis report).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/considering-using-ivf-to-have-a-baby-heres-what-you-need-to-know-108910">Considering using IVF to have a baby? Here's what you need to know</a>
</strong>
</em>
</p>
<hr>
<h2>How does it work?</h2>
<p>The guide is designed for heterosexual couples and for women who are trying to get pregnant with a known sperm donor, where: </p>
<ul>
<li><p>the woman has regular menstrual cycles</p></li>
<li><p>the woman has at least one open fallopian tube </p></li>
<li><p>the woman is 42 or younger</p></li>
<li><p>the man has had a sperm test. </p></li>
</ul>
<figure class="align-center ">
<img alt="A couple sit on the doorstep talking. The man is holding a tablet computer." src="https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381842/original/file-20210202-23-kh6l8y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This new online tool aims to inform your decisions around fertility treatment.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Four questions ask about the four factors most likely to affect a woman’s chance of conception, described above.</p>
<p>The responses are then fed into the algorithm, which estimates the chance of pregnancy over the next 12 months in three different scenarios: </p>
<ul>
<li><p>you just keep trying</p></li>
<li><p>you have six cycles of IUI</p></li>
<li><p>you have two cycles of IVF. </p></li>
</ul>
<p>This information can help people consider their options and decide about next steps. </p>
<p>If your estimated chance of spontaneous pregnancy in the next 12 months is 30% or more, you have a good chance of avoiding the need for expensive fertility treatments. But if you’re not pregnant after six months, the guide suggests seeking advice from a fertility specialist about the next steps. </p>
<p>If your estimated chance without treatment is less than 30%, it’s best to see a fertility specialist as soon as possible.</p>
<h2>A word of caution</h2>
<p>While the guide can help you explore your options and consider next steps, the estimates it gives are based on averages of data from large studies of people with unexplained infertility. </p>
<p>This means it shouldn’t replace advice from a fertility specialist, who will hopefully use the <a href="https://www.rbmojournal.com/article/S1472-6483(19)30629-7/fulltext">available evidence</a> to recommend the best way forward for you, considering your personal circumstances and preferences.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/womens-fertility-does-egg-timer-testing-work-and-what-are-the-other-options-109726">Women's fertility: does 'egg timer' testing work, and what are the other options?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/153636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karin Hammarberg receives funding from the Australian Government. </span></em></p>The guide asks questions about the woman’s age, how long she has been trying for a baby, whether she has been pregnant before, and the percentage of the male partner’s sperm that move normally.Karin Hammarberg, Senior Research Fellow, Global and Women's Health, School of Public Health & Preventive Medicine, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1004782019-06-20T13:43:50Z2019-06-20T13:43:50ZSix amazing facts you need to know about ants<figure><img src="https://images.theconversation.com/files/280292/original/file-20190619-171183-p0runh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Black_Garden_Ant_tending_Citrus_Mealybug_(15876770928).jpg">Katja Schulz</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Have you have seen ants this year? In Britain, they were probably black garden ants, known as <em>Lasius niger</em> – Europe’s most common ant. One of somewhere between <a href="http://science.sciencemag.org/content/312/5770/101">12,000 and 20,000 species</a>, they are the scourge of gardeners – but also fascinating. </p>
<p>The small, black, wingless workers run around the pavements, crawl up your plants tending aphids or collect tasty morsels from your kitchen. And the <a href="https://theconversation.com/the-amazing-secrets-behind-flying-ant-day-79686">flying ants</a> that occasionally appear on a warm summer’s evening are actually the reproductive siblings of these non-winged workers. Here’s what else you need to know:</p>
<h2>1. Most ants you see are female</h2>
<p>Ants have a <a href="https://www.youtube.com/watch?v=t-2BpBjId1c">caste system</a>, where responsibilities are divided. The queen is the founder of the colony, and her role is to lay eggs. Worker ants are all female, and this sisterhood is responsible for the harmonious operation of the colony. </p>
<p>Their tasks range from caring for the queen and the young, foraging, policing conflicts in the colony, and waste disposal. Workers will most likely never have their own offspring. The vast majority of eggs develop as workers, but once the colony is ready the queen produces the next generation of reproductives which will go on to start own colonies.</p>
<p>A female ant’s fate to become a worker or queen is mainly <a href="https://www.journals.uchicago.edu/doi/10.1086/590961">determined by diet</a>, not genetics. Any female ant larva can become the queen – those that do receive diets richer in protein. The other larvae receive less protein, which causes them to <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/een.12337">develop as workers</a>.</p>
<h2>2. Male ants are pretty much just flying sperm</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=819&fit=crop&dpr=1 600w, https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=819&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=819&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1029&fit=crop&dpr=1 754w, https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1029&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/280287/original/file-20190619-171271-5dtywo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1029&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Male ants have a mother but no father.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Unlike humans, with X and Y chromosomes, an ant’s sex is determined by the <a href="https://frontiersinzoology.biomedcentral.com/articles/10.1186/1742-9994-3-1">number of genome copies it possesses</a>. Male ants develop from unfertilised eggs so receive no genome from a father. This means that male ants don’t have a father and cannot have sons, but they do have grandfathers and can have grandsons. Female ants, in comparison, develop from fertilised eggs and have two genome copies – one from their father and one from their mother.</p>
<p>Male ants function like flying sperm. Only having one genome copy means every one of their sperm is genetically identical to themselves. And their job is over quickly, dying soon after mating, although their sperm live on, <a href="https://jeb.biologists.org/content/jexbio/221/6/jeb173435.full.pdf">perhaps for years</a>.
– essentially their only job is to reproduce. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/280045/original/file-20190618-118543-13mbljf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Let them eat cake.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>3. After sex queens don’t eat for weeks</h2>
<p>When the conditions are warm and humid, the winged virgin queens and males leave their nests in search of mates. This is the behaviour seen on “<a href="https://www.independent.co.uk/news/science/fly-ant-day-when-is-what-why-explained-nuptial-flight-uk-london-a8431871.html">flying ant day</a>”. In <em>L. niger</em>, mating takes place on the wing, often hundreds of meters up (hence the need for good weather). Afterwards, queens drop to the ground and shed their wings, while males quickly die. Mated queens choose a nest site and burrow into the soil, made softer from recent rain. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-amazing-secrets-behind-flying-ant-day-79686">The amazing secrets behind 'flying ant day'</a>
</strong>
</em>
</p>
<hr>
<p>Once underground, the queens will not eat for weeks – until they have produced their own daughter workers. They use energy from their fat stores and redundant flight muscles to lay their first batch of eggs, which they fertilise using sperm stored from their nuptial flight. It is the same stock of sperm acquired from long dead males that allows a queen to continue laying fertilised eggs for her entire life. Queens never mate again.</p>
<h2>4. Home-making the ant way: cooperation, death and slavery</h2>
<p>Sometimes two <em>L. niger</em> queens unite to found a nest. This initially cooperative association – which increases the chance of establishing a colony – dissolves once new adult workers emerge and then the queens fight to the death. More sinister still, <em>L. niger</em> colonies sometimes steal brood from their neighbours, putting them to work as slaves. </p>
<p>Slave-making has evolved in a number of ant species, but they also display cooperation at extraordinary levels. An extreme example of this is a “supercolony” of Argentine ants (<em>Linepithema humile</em>) which extends over 6,000km of European coastline from Italy to north-west Spain, and is composed of literally <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC122904/">billions of workers from millions of cooperating nests</a>.</p>
<h2>5. Queen ants can live for decades, males for a week</h2>
<p>After establishing her colony, the queen’s work is not done and she has many years of egg-laying ahead of her. In the laboratory, <em>L. niger</em> queens have lived for <a href="http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_34.shtml">nearly 30 years</a>. Workers live for about a year, males little more than a week (although their sperm live longer). These extraordinary differences in longevity are purely due to the way their genes are switched on and off.</p>
<h2>6. Ants can help humans and the environment</h2>
<p>Ants have a major influence in ecosystems worldwide and their roles are diverse. While some ants are considered pests, others act as <a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev.en.37.010192.002403">biological-control agents</a>. Ants benefit ecosystems by <a href="https://www.jstor.org/stable/24996901?seq=1#page_scan_tab_contents">dispersing seeds</a>, <a href="https://brill.com/abstract/journals/tar/4/2/article-p157_4.xml">pollinating plants and improving the quality of soil</a>. Ants might also benefit our health, as a potential source of new medicines such as <a href="https://theconversation.com/antibiotic-resistance-fight-could-get-a-little-help-from-ants-91412">antibiotics</a>. </p>
<p>So when you next see an ant, before you think to kill her, consider how fascinating she really is.</p><img src="https://counter.theconversation.com/content/100478/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charlie Durant receives funding from the Biotechnology and Biological Sciences Research Council (BBSRC).</span></em></p><p class="fine-print"><em><span>Max John receives funding from the Biotechnology and Biological Sciences Research Council (BBSRC), and the Genetics Society. </span></em></p><p class="fine-print"><em><span>Rob Hammond receives funding from NERC, BBSRC, The Genetics Society.</span></em></p>They might be a hated household pest, but ants actually live fascinating and complex lives.Charlie Durant, PhD Candidate, Department of Genetics and Genome Biology, University of LeicesterMax John, PhD Candidate, Department of Genetics and Genome Biology, University of Leicester, University of LeicesterRob Hammond, Lecturer, Department of Genetics and Genome Biology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1138172019-03-21T18:04:02Z2019-03-21T18:04:02ZA new procedure may preserve fertility in kids with cancer after chemo or radiation<figure><img src="https://images.theconversation.com/files/265022/original/file-20190321-93028-tlxss5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C788%2C592&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A 12-week-old baby female macaque, named Grady, was born from frozen testicular tissue. </span> <span class="attribution"><span class="source">Oregon Health and Science University</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Cancer in children was often a death sentence in decades past, but new therapies are saving lives. Many of these treatments such as chemotherapy and radiation, however, make children infertile. Now, new research is showing one strategy to preserve their fertility so that someday they can have their own biological children.</p>
<p>Many childhood cancer survivors have remained beyond the reach of current assisted reproductive technologies because they are not able to produce mature sperm or eggs. Adult patients have the option to freeze eggs or sperm before treatment and use those samples in the future to achieve pregnancy using assisted reproductive technologies. Unfortunately, those options are not available to children who are not yet able to produce mature eggs or sperm.</p>
<p>Now <a href="http://orwiglab.org.s104505.gridserver.com/lab-members/kyle-orwig/">I</a> and my colleagues in <a href="http://orwiglab.org">the Orwig lab</a> at the Magee-Womens Research Institute of the University of Pittsburgh Medical Cancer have developed a next-generation reproductive technology by figuring out <a href="http://science.sciencemag.org/cgi/doi/10.1126/science.aav2914">how to preserve fertility in pediatric cancer patients</a> who might face infertility after chemotherapy or radiation.</p>
<h2>Pediatric cancer therapies</h2>
<p>About <a href="https://curesearch.org/Childhood-Cancer-Statistics">40,000 kids undergo cancer treatments</a> each year, and 80 percent of children will survive and can look forward to a full and productive life. The bad news is that treatment comes at a cost: About 30 percent of adult survivors of these childhood cancers discover that their lifesaving cancer treatment had an unintended side effect – infertility. Cancer survivors report that fertility is important to them, and while adoption or other family building options are available, those options are not always accessible or desired. </p>
<p>In our current study, we used a juvenile male macaque to test whether it was possible to collect and then freeze immature testicular tissues – which produce mature sperm only after puberty. </p>
<p>We began our experiment by surgically removing this tissue from macaques, which we immediately froze. As the animals neared puberty, the testicular tissue was thawed and grafted just under the skin of the same monkey’s back or scrotum. </p>
<p>The grafts matured during the next several months under the influence of pubertal hormones from the brain. The grafts grew and produced testosterone, which is required for sperm production. We retrieved the testicular tissues eight to 12 months after the grafting procedure, dissected it and discovered that all of the grafted tissue produced mature sperm. </p>
<p>My team then collected this sperm and sent it to our collaborators in the <a href="https://www.ohsu.edu/xd/research/centers-institutes/onprc/research-services/research-support/art-esc.cfm">Assisted Reproductive Technology Core of the Oregon National Primate Research Center</a> at the Oregon Health and Science University, who injected it into an egg from a female macaque – a procedure called <a href="https://www.cdc.gov/art/key-findings/icsi.html">intracytoplasmic sperm injection</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=349&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=349&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265043/original/file-20190321-93044-1o3ckd9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=349&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In the intracytoplasmic sperm injection process, a single sperm is injected directly into an egg. This is how the team at the Oregon Health Sciences University created Grady.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-rendering-icsi-intracytoplasmic-sperm-injection-745613476">medistock/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>We then checked the eggs to see which ones were successfully fertilized by the sperm. Eleven of the resulting embryos were transferred into six surrogate female macaques, resulting in one pregnancy that produced a healthy baby girl that we named Grady, which stands for graft-derived baby. </p>
<p>This is the first study to prove that sperm from frozen and thawed primate testicular tissue grafts were able to fertilize eggs and produce a healthy baby. </p>
<h2>Implications for the human fertility clinic</h2>
<p>The freezing and thawing aspect is important because a prepubertal cancer patient may need to keep their testicular or ovarian tissue in frozen storage for years or even decades before they need them for reproductive purposes. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=874&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=874&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=874&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1098&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1098&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265040/original/file-20190321-93032-uh3ayv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1098&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Grady, here at 11 months, was born from frozen testicular tissue.</span>
<span class="attribution"><span class="source">Oregon Health and Science University</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Combined with nearly two decades of work by other researchers in <a href="http://doi.org/10.1038/nature00918">mice</a>, <a href="https://doi.org/10.1371/journal.pone.0070989">pig</a> and <a href="http://doi.org/10.1095/biolreprod.103.025536">monkey</a> models, we believe that <a href="http://science.sciencemag.org/cgi/doi/10.1126/science.aav2914">our results provide important preclinical safety and feasibility</a> data to justify translating this technique to the human fertility clinic in the next two to five years. </p>
<p>I believe we owe this to our patients who have already accepted the risk of testicular biopsy surgery and trusted us to develop next-generation reproductive therapies.</p>
<p>Academic centers around the world, including the <a href="https://mageewomens.org/research/research-centers/fertility-preservation-program/">Fertility Preservation Program of UPMC</a>, are freezing testicular tissues for boys and ovarian tissues for girls in anticipation that those tissues can be matured in the future to produce sperm or eggs and biological offspring. </p>
<p>There is one documented case of an adult survivor of a childhood cancer who had a <a href="http://doi.org/10.1093/humrep/dev128">baby after her frozen ovarian tissues were transplanted</a> back into her body. There are no documented births from frozen testicular tissues. Our group has been <a href="https://fertilitypreservationpittsburgh.org/">freezing testicular tissue for boys and ovarian tissues for girls</a> since 2011 and has preserved tissues for nearly 250 patients (206 testicular tissues and 41 ovarian tissues). </p>
<p>Therefore, <a href="http://orwiglab.org/">our laboratory</a> is committed to responsibly developing the next generation of assisted reproductive technologies that will allow our patients to use their tissues to achieve their reproductive goals. </p>
<p>All patients should be informed about the reproductive side effects of their medical treatments and about <a href="https://fertilitypreservationpittsburgh.org/">options to preserve their fertility</a> immediately at the time of diagnosis. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/C_F5awyrums?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Kyle Orwig describes how this team harvested tissue, froze and thawed it, and used it to produce mature sperm that successfully fertilized an egg.</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/113817/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kyle Orwig receives funding from the Eunice Kennedy Shriver National Institute for Child Health and Human Development.</span></em></p>Children with cancer not only endure chemotherapy or radiation treatment but they may also face infertility in adulthood. Now a new procedure, just proven in monkeys, may be close to use in humans.Kyle Orwig, Professor of OB/GYN and Reproductive Sciences, University of PittsburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1136952019-03-20T09:15:24Z2019-03-20T09:15:24ZHow we solved the mystery of the human sperm tail – and what it could mean for the future of IVF<figure><img src="https://images.theconversation.com/files/264678/original/file-20190319-60990-ldgwyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">shutterstock</span></span></figcaption></figure><p>Every time a man ejaculates about <a href="https://www.who.int/reproductivehealth/en/">55m sperm are released</a>. This is equivalent to more than six times the entire population of London or New York, and more than twice the population of Shanghai city. </p>
<p>But of course, not all of these sperm will go on to become babies. In fact only around 15 sperm are able to make it through the female reproductive tract. This is because for a sperm, the journey to fertilise an egg is a treacherous one. And now, <a href="http://dx.doi.org/10.1098/rsif.2018.0668">our new research</a> has discovered what gives human sperm the strength to succeed in the race to fertilise the egg – and it’s all to do with their tails.</p>
<p>In the reproductive tract, sperm encounter a complex chemical and physical landscape. A sperm must escape the deadly acids of the vagina, penetrate the thick cervical mucus barrier – this is around a hundred times thicker than water – not get trapped in a cervical crypt that leads to nowhere, endure uterine contractions, to eventually find the tiny opening that leads to the oviducts – the tube through which an egg passes from an ovary. This is all while being attacked in the uterus by white blood cells. </p>
<p>This all takes place before a sperm can penetrate another thick protective layer that surrounds the egg. All this may sound excessively difficult for the tiny sperm, but these barriers are there for protection – the uterus is designed to receive a baby, and the sperm could be an invading force carrying diseases. </p>
<p>Our research has discovered that it is a reinforced outer layer which coats the tails of human sperm that gives them the strength to make the powerful rhythmic strokes needed to break through this jelly-like cervical mucus blockage.</p>
<h2>Making the discovery</h2>
<p>Sperm tails –- or flagella –- measure just the breadth of a hair in length and are incredibly complex. So to find out more about how they work, we used a virtual sperm model to compare the tails of sperm from humans and other mammals (which fertilise inside the body) with sperm from sea urchins (which fertilise in open water outside the body).</p>
<p>We found that although the tails of sea urchin and human sperm share the same bendy inner core, it seems that the tails of sperm in mammals may have evolved a reinforcing outer layer. This outer layer, or “cape”, gives them the exact amount of extra strength and stability needed to overcome the thick fluid barrier they come up against in internal fertilisation.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264207/original/file-20190316-28499-1b1gih3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Virtual sperm with and without the reinforcing ‘cape’.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Using our virtual sperm model, we created a “Frankenstein” sperm by adding and removing features of the tails from different species so that we could identify how each one functions. We also increased the liquid viscosity for the various sperms to swim through. What we found was that, when the virtual sea urchin-like sperm was made to swim through liquid as viscous as cervical mucus, their tails quickly buckled under the pressure – which meant they were unable to propel themselves forward. In many cases this “trapped” the sperm to <a href="https://doi.org/10.1098/rsif.2010.0136">swim in circles</a>.</p>
<p>Human sperm on the other hand, thrashed around wildly in a low-viscosity liquid like water, but in thicker liquids they swam with a powerful rhythmic wave. This is also found in actual experiments with sea urchin sperm and human sperm swimming in thick substances. Of course, we don’t know which adaptation came first, the stronger sperm or the cervical mucus – or whether they co-evolved. </p>
<h2>Finding the fittest sperm</h2>
<p>But these findings are not only interesting from an evolutionary perspective – they could also help to lead to better sperm selection methods in fertility clinics, which would enable doctors to easily identify the fittest sperms.</p>
<p>In the UK, one in seven couples are classed as having reduced fertility – and sperm dysfunction is the most common cause. Sperm count in <a href="https://academic.oup.com/humupd/article/23/6/646/4035689">Western men has halved since 1970</a> and male fertility has become a global challenge. One in six couples receive fertility treatment in the UK – and for every 100 children born, one of those children will have been conceived by <a href="http://fertilitynetworkuk.org/">IVF</a>.</p>
<p>But it is also very difficult to have a baby via IVF – one in four pregnancies ends in miscarriage. Birth success rates from IVF in the UK range from <a href="https://www.hfea.gov.uk/treatments/explore-all-treatments/in-vitro-fertilisation-ivf/">2% to 33%</a> depending on the woman’s age – with under-35s standing a much higher chance. And if you do need to pay for treatment, one single cycle of IVF including fertility drugs normally costs between £3000 and £5000. NHS only provides up to three IVF full cycles – but this can depend on the postcode lottery of <a href="http://fertilitynetworkuk.org/postcodelottery/">where you live and what your GP can offer</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264683/original/file-20190319-60949-zygk5o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The findings could be a game changer for the way healthy sperm are selected at IVF clinics.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Our research highlights the precise adaptation of the human sperm tail that enables it to swim in the cervical mucus – and this emphasises the importance of imitating the natural selection of the reproductive tract while assessing and screening sperm for use in IVF. </p>
<p>This is an important finding as the current “sperm count” used in clinics is a poor predictor of fertility and high-viscosity fluids imitating the cervical mucus are still not currently used in clinics. It is clear then that more research and in-depth clinical tests are now needed to assess the impact of our findings on future IVF rounds.</p><img src="https://counter.theconversation.com/content/113695/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hermes Bloomfield-Gadêlha does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Our new research has discovered what gives human sperm the strength to succeed in the race to fertilise the egg – and it’s all to do with their tails.Hermes Bloomfield-Gadêlha, Lecturer in Applied Mathematics, University of YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1117112019-02-15T09:37:49Z2019-02-15T09:37:49Z‘Older sperm’ produce healthier offspring<figure><img src="https://images.theconversation.com/files/258984/original/file-20190214-1721-1wvoulf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/medically-accurate-illustration-human-sperms-319477082?src=5uLcwOZW_AwE1Bh283jawQ-1-5">Sebastian Kaulitzki/Shutterstock</a></span></figcaption></figure><p>Sperm differ markedly in their swimming performance. This difference not only determines their success at fertilising an egg but may have direct consequences for the resulting offspring, our <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/evl3.101">latest study</a> shows. We found that selecting the longer-lived sperm in the ejaculate of zebrafish results in offspring that live longer and have more offspring compared with their siblings sired by the shorter-lived sperm from the same ejaculate.</p>
<p>For our study, we collected the ejaculate of 26 male zebrafish and divided them into two batches. In one batch, we activated sperm with water and added them immediately to half the eggs of a female, giving all sperm that could move an opportunity to fertilise an egg. In the second batch, we activated sperm but waited 25 seconds until half the sperm could no longer move, allowing only the longer-lived sperm to fertilise eggs. </p>
<p>We reared the resulting offspring to adulthood and measured their lifespan and the number and survival of the offspring they produced throughout life. This design enabled us to directly compare full siblings sired by shorter- and longer-lived sperm from the same male. Offspring sired by “older” sperm not only lived significantly longer but also produced more and healthier offspring. </p>
<p>Interestingly, the effects differed between male and female offspring. Males sired by longer-lived sperm had more and healthier offspring than males sired by shorter-lived sperm, throughout their lives. </p>
<p>The effect of sperm selection on females was more variable. Females sired by longer-lived sperm produced more offspring throughout life, but offspring survival rates declined with age. Females sired by shorter-lived sperm produced fewer offspring throughout life, but the health of the offspring they produced later in life was better than the offspring they produced early in life. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/258986/original/file-20190214-1721-1nos18i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Zebrafish.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/212364877?src=H0QFfOhd8co7e167_BM40w-1-2&size=medium_jpg">Kazakov Maksim/Shutterstock</a></span>
</figcaption>
</figure>
<h2>All sperm are not equal</h2>
<p>Our research shows that selection, even among perfectly fertile sperm in the ejaculate of a male, has direct consequences for the health of the resulting offspring. Our findings challenge the idea that all sperm that can fertilise an egg are equivalent in siring healthy offspring. </p>
<p>Some of the variation in sperm traits in an ejaculate may be attributed to “errors” during sperm production. But the fact that the variation in swimming duration among sperm in an ejaculate has effects across generations suggests that other mechanisms are involved.</p>
<p>Sperm within an ejaculate not only differ in swimming performance but also in the combination of genes they carry. On average, two sperm produced by one male share 50% of their genes. This is because the duplicate set of genes of the male are distributed more or less randomly between sperm. In <a href="https://www.ncbi.nlm.nih.gov/pubmed/28698378">an earlier study</a> from our lab, we showed that sperm selected for longevity differ in their genes. This finding provides a direct link between sperm phenotype (how it looks and behaves) and sperm genes and supports the idea that the genetic variation among sperm contributes to the variation in swimming duration. </p>
<p>The role of the genes that a sperm carries in determining sperm swimming performance provides a plausible explanation for the differences we noted in the offspring later in life. Our selection does not simply select for older sperm but for sperm with endurance.</p>
<h2>Trade-off</h2>
<p>Biologists believe that in ageing there is a trade-off between the number of offspring and lifespan, that is, the more offspring a creature has, the shorter its lifespan, and vice versa. Our results suggest the opposite, namely that offspring that live longer also produce more offspring. Although this needs further investigation, it appears that our selection on sperm swimming duration ends up in selecting for better sperm. By waiting for half of the sperm to die, we get rid of the worst sperm.</p>
<p>If the benefits of longer-lived sperm are so striking, why do shorter-lived sperm even exist? Conditions during fertilisation vary and factors such as the timing between sperm and egg release or water temperature may favour different sperm traits. Longer-lived sperm will be at an advantage if the female delays egg laying by even a few seconds or increases the distance between sperm and eggs. </p>
<p>We still know surprisingly little about the processes occurring between the end of sperm production and the moment of fusion between sperm and egg. Our findings emphasise the need for more studies on this subject as they may have implications for fertilisation technologies used in fertility clinics. These technologies often skip several, if not all, possible steps of selection before fertilisation. Understanding which sperm traits are determining offspring survival and health may help improve the success rate of the existing methods.</p><img src="https://counter.theconversation.com/content/111711/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simone Immler receives funding from the European Research Council and the Knut and Wallenberg Foundation (Sweden). Co-author (Ghazal Alavioon) is affiliated with Uppsala University. </span></em></p>Zebrafish study could have implications for human fertilisation technology.Simone Immler, Associate Professor, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1096832019-01-11T13:00:51Z2019-01-11T13:00:51ZHow men’s damaged sperm could play significant role in recurrent miscarriage<figure><img src="https://images.theconversation.com/files/253257/original/file-20190110-43538-1t1ba9z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Shows spunk, but trouble down the line.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/human-sperm-selection-sorting-reproductive-concept-167714144?src=BKZ7HK6K5lSML7UQVeta3A-1-6">Lightspring/Shutterstock</a></span></figcaption></figure><p>It’s an unfortunate fact that one in four pregnancies will end in a miscarriage, typically <a href="https://www.nct.org.uk/pregnancy/miscarriage/miscarriage-your-questions-answered">within the first 12 weeks of pregnancy</a>. In most cases, this will be a single, one-off event with the underlying biological cause unknown. However, around 1% of couples will suffer the agony that is recurrent miscarriage. </p>
<p>Recurrent miscarriage is typically defined as the <a href="https://www.tommys.org/pregnancy-information/pregnancy-complications/baby-loss/miscarriage/types-miscarriage/recurrent-miscarriage">loss of three or more pregnancies in a row</a>. As the mother carries the pregnancy, the traditional belief has been that the underlying cause of miscarriage resides with her. But maternal factors such as hormone imbalance or an inability for the womb to support the pregnancy <a href="https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_17.pdf">only account for about half</a> of recurrent miscarriages. It’s clear, then, that other unknown factors apart from maternal health play a significant role in miscarriage risk. This lack of understanding has lead researchers to investigate whether the quality of a father’s sperm may be involved.</p>
<h2>Healthy fathers, healthy sperm</h2>
<p>Before becoming pregnant, many women will assess and modify their current lifestyle choices, for example drinking or smoking less, in order to ensure a healthy pregnancy. But the health of the father at the time of conception is one factor that is often overlooked. We now know that <a href="https://www.nhs.uk/common-health-questions/mens-health/how-can-i-improve-my-chances-of-becoming-a-dad">the quality of a man’s sperm</a> is directly linked to his health. </p>
<p>Excessive alcohol consumption, smoking, stress – and even the type of underpants he wears – <a href="https://theconversation.com/why-men-need-to-think-about-their-fertility-too-72063">can all affect the quality of a man’s sperm</a>. One of the biggest factors affecting sperm quality is obesity. In many countries, while rates of obesity <a href="https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight">have been increasing</a>, male fertility <a href="http://www.independent.co.uk/news/science/scientists-warn-of-sperm-count-crisis-8382449.html">has been declining</a>. Studies in both men and mice show that sperm from overweight males are less motile, are less likely to fertilise an egg and are <a href="https://rep.bioscientifica.com/view/journals/rep/154/4/REP-17-0161.xml">less likely result in a healthy birth</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-men-need-to-think-about-their-fertility-too-72063">Why men need to think about their fertility too</a>
</strong>
</em>
</p>
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<h2>Sperm DNA fragmentation</h2>
<p>The prime goal of sperm is to fertilise the egg and pass on the father’s genes to the next generation. It is therefore essential that the DNA contained within the sperm is not damaged or fragmented. Studies have shown that factors such as poor diet, being overweight, smoking, infection and pollution <a href="https://www.reproductivehealthgroup.co.uk/fertility-treatments/assessments/men/dna-fragmentation/">all increase how fragmented the DNA is</a> within sperm. As sperm cannot repair their damaged DNA, high levels of sperm DNA fragmentation is viewed as a leading cause of infertility in men. </p>
<p>Researchers now believe that high levels of sperm DNA fragmentation are also linked with increased risk of miscarriage and <a href="http://clinchem.aaccjnls.org/content/65/1/161">a recent study</a> demonstrated a link between sperm DNA fragmentation and recurrent miscarriage. </p>
<p>Researchers from Imperial College London studied the quality of sperm in men whose partners had suffered with recurrent miscarriage. They then compared those sperm with sperm from men whose partners had not experienced miscarriage. They saw that sperm DNA fragmentation levels were twice as high in men whose partners suffered with recurrent miscarriage than in the control group. </p>
<p>The researchers also found that the levels of a group of molecules called “reactive oxygen species” were four times higher in men with DNA damaged sperm. Reactive oxygen species are produced naturally by every cell, and small amounts are necessary for male reproduction. However, at higher concentrations, reactive oxygen species <a href="https://tdlpathology.com/services-divisions/tdl-andrology/reactive-oxygen-species-and-male-infertility/">can damage sperm cells and their DNA</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253255/original/file-20190110-43532-74yn7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Winner shows spunk, but trouble may be down the line.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hand-drawing-sperm-on-blackboard-464817722?src=ujTOqcIG4N3pr6Tq9Lf9Ow-1-0">Piya Kunkayan/Shutterstock</a></span>
</figcaption>
</figure>
<p>The researchers also noted that the men whose partners suffered from recurrent miscarriage were also heavier than the control men as well as older. Recently, there has been a lot of interest <a href="https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/expert-answers/paternal-age/faq-20057873">in the relationship</a> between a father’s age, the quality of his sperm and the health of his offspring. As men produce sperm throughout their lifetime, the belief has been that age does not affect a man’s fertility. However, recent studies have suggested that a father’s age at the time of conception might affect the health of his children. </p>
<p>Some studies <a href="https://www.fertstert.org/article/S0015-0282(16)63091-1/pdf">have shown</a> that for men over 40, there is an increased risk for miscarriage, rare birth defects, autism, schizophrenia and some types of cancer such as leukaemia. Studies in mice and humans also suggests that poor paternal diet (too much or too little) <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5920283/">can influence</a> the long-term health of offspring, increasing their chances of developing obesity, diabetes and/or heart disease.</p>
<p>The link between a male’s health and well-being of a male and the quality of his sperm is now well established. It is also becoming apparent that sperm quality influences a range of factors including a man’s fertility, the likelihood of him becoming a father and even the long-term health of his children. However, more research is needed to understand the links between the health of a father, the quality of his sperm and the well-being of his offspring. </p>
<p>Much of the fundamental research to date has been conducted in animals. As such, it is vital that we now establish whether the same effects are seen in humans. What is clear though is that both prospective parents in couples who intend on becoming parents should assess their current lifestyle habits to maximise their chances of a healthy pregnancy.</p><img src="https://counter.theconversation.com/content/109683/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Watkins current research is funding by the Biotechnology and Biological Sciences Research Council (BBSRC). </span></em></p>Traditional belief has held that the underlying cause of miscarriage can be found in mothers, but half of recurrent miscarriages have another cause.Adam Watkins, Assistant Professor, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1073752019-01-07T14:28:55Z2019-01-07T14:28:55ZClimate change: effect on sperm could hold key to species extinction<figure><img src="https://images.theconversation.com/files/252638/original/file-20190107-32139-y9hdya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/skull-on-desert-58522480?src=5RTUr9LQgKjOeuj47ESMcw-1-5">Wong Yu Liang/Shutterstock</a></span></figcaption></figure><p>Since the 1980s, <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(17)30082-7/fulltext">increasingly frequent and intense heatwaves</a> have contributed to more deaths than any other extreme weather event. The fingerprints of extreme events and climate change are widespread in the natural world, where populations are showing stress responses.</p>
<p>A common fingerprint of a warmer world is a range shift, where the distribution of a species moves to higher altitudes or migrates toward the poles. A review of several hundred studies found an <a href="https://www.ncbi.nlm.nih.gov/pubmed/21852500">average shift of 17km poleward, and 11 metres upslope</a>, every decade. However, if temperature changes are too intense or lead species to geographic dead ends, local extinctions occur in the heat.</p>
<p>In 2003, <a href="https://www.ncbi.nlm.nih.gov/pubmed/12511952" title=") of climate change on natural populations. [Significant and simultaneous stress responses](https://www.ncbi.nlm.nih.gov/pubmed/22257223 "">80% of relevant studies found the fingerprints</a> were seen among species, from grasses to trees and molluscs to mammals. Some migrated, some changed colour, some altered their bodies and some shifted their life cycle timings. A recent review of more than 100 studies found <a href="http://science.sciencemag.org/content/348/6234/571">8-50% of all species</a> will be threatened by climate change as a result. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/HCYGxViPiPA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>High temperatures and extinctions</h2>
<p>Currently, we have a <a href="https://www.ncbi.nlm.nih.gov/pubmed/23075836">disturbingly limited knowledge</a> of which biological traits are sensitive to climate change and therefore responsible for local extinctions. However, a potential candidate is male reproduction, because a range of medical and agricultural studies <a href="https://pdfs.semanticscholar.org/2291/2f5bb3a55579381a5e92cab3a142f94639a1.pdf">in warm blooded animals</a> have shown that male infertility happens during heat stress.</p>
<p>However, until recently this had <a href="https://www.ncbi.nlm.nih.gov/pubmed/16033555">rarely been explored outside fruit flies</a> in cold blooded animals. This is despite the fact that ectotherms – organisms that rely on heat in their environment to maintain a suitable body temperature – comprise most of biodiversity. Astonishingly, nearly <a href="https://www.ncbi.nlm.nih.gov/pubmed/26034274">25% of all species</a> are thought to be a beetle.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=753&fit=crop&dpr=1 600w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=753&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=753&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=946&fit=crop&dpr=1 754w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=946&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=946&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The red flour beetle. The ubiquity of beetles prompted biologist J.B.S. Haldane to say that God has ‘an inordinate fondness for beetles’.</span>
<span class="attribution"><span class="source">Martin Taylor</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The red flour beetle (<em>Tribolium castaneum</em>) is a useful ectotherm for <a href="https://www.ncbi.nlm.nih.gov/pubmed/18429767">large experiments on reproduction</a>, as they can go from egg to adult in a month at 30°C. Females can store male sperm in specialised organs called spermathecae and they only need to keep 4% of a single ejaculate to enable them to produce offspring for up to 150 days.</p>
<p>To look at the <a href="https://www.nature.com/articles/s41467-018-07273-z">impact of heatwaves on reproduction</a>, beetles were exposed to either standard control conditions or five-day heatwave temperatures, which were 5°C to 7°C above their preferred temperature. Afterwards, beetles mated and a variety of experiments looked for damage to their reproductive success, sperm form and function, and offspring quality.</p>
<p>We found that 42°C heatwave temperatures halved the number of offspring males could produce relative to 30°C, with some males failing to produce any and mature sperm in female storage also experiencing damage from heatwaves. However, the reproductive output of pairs where only the females endured a five-day heatwave event was similar in all temperatures.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=250&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=250&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=250&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=314&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=314&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=314&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Heated males (B) had less sperm (stained green) and relatively more dead sperm (stained red) than control males (A).</span>
<span class="attribution"><span class="source">Kris Sales</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The decline was likely due to a combination of males becoming worse at mating, less sperm being transferred, less sperm transferred being alive, less sperm being kept in the females’ spermathecae and more sperm being damaged and infertile.</p>
<p>Two results were particularly concerning. These beetles, and many cold-blooded animals, can live for years and are likely to see multiple heatwaves. When we exposed males to two heatwave events, ten days apart, their offspring production was less than 1% of that of unheated males. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/wildlife-winners-and-losers-in-britains-summer-heatwave-100408">Wildlife winners and losers in Britain's summer heatwave</a>
</strong>
</em>
</p>
<hr>
<p>This suggests that successive heatwaves can compound the damage of previous ones. The damage to offspring longevity and male fertility was another effect which was compounded over successive generations, and could lead to spiralling population declines.</p>
<p>Knowing what aspects of biology higher temperatures could compromise is essential to understanding how climate change affects nature. Hopefully, this new knowledge can help predict which species are most likely to be vulnerable, allowing conservationists to prepare for the trouble ahead.</p><img src="https://counter.theconversation.com/content/107375/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kris Sales does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Climate change threatens to cause mass extinctions – but how, exactly? New research suggests male fertility may be the weakest link.Kris Sales, PhD Candidate in evolution, behaviour, ecology and entomology, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1047542018-11-07T21:53:18Z2018-11-07T21:53:18ZMeet the men who donate sperm on Facebook<figure><img src="https://images.theconversation.com/files/244171/original/file-20181106-74757-6gnjp0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">While media portrayals of online sperm donation often portray "rogue breeders" or "super sperm," research reveals that the real men who do this are motivated to help others. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>George (not his real name) is 24 and single. In the past four years, he has helped three couples get pregnant. The first couple had two sons. The second couple had a girl. And the third couple just found out they are expecting. A participant in my research, he said: </p>
<blockquote>
<p>“I’m making a huge impact on these people’s lives. Why not keep helping them out?”</p>
</blockquote>
<p>Like George, an increasing number of men are going online to make arrangements to donate sperm through Facebook or connection websites. <a href="https://doi.org/10.3109/14647273.2014.881561">Online sperm donation</a> gives donors ultimate freedom in selecting who they will help, engaging with the recipients and negotiating the terms and conditions of the donation.</p>
<p>Just as Uber transformed the taxi business and Airbnb shook up the hotel world, online sperm donation is the sperm bank, reinvented. Yet, as more people turn to the accessibility and convenience of online sperm donation, surprisingly little is known about the men who donate.</p>
<p>Media portrayals of online sperm donation are often coloured by fiery references to <a href="http://nymag.com/news/features/trent-arsenault-2012-2/">dangerous rogue breeders</a>, <a href="https://www.mirror.co.uk/news/us-news/sperm-donor-who-advertises-facebook-12889072">“super” seed</a> and <a href="https://abovethelaw.com/2016/09/i-want-to-put-a-baby-in-you-extreme-sperm-donation/">sperm donation scandals</a>, highlighting dramatic cases that would be well-suited for reality TV programs.</p>
<p>Certainly, the potential risks of online sperm donation — like any online activity — should not be understated. However, a more balanced perspective of online sperm donation is important to better understand the practice and its implications for the men, women and children who are part of it. </p>
<p>To address this need, I developed a research project with fellow PhD candidate Celine Delacroix as part of our doctoral program at the University of Ottawa. The results are <a href="https://doi.org/10.1080/09581596.2018.1492704">published in the journal <em>Critical Public Health</em></a>. </p>
<h2>A way to help others</h2>
<p>We gathered the stories of six men who participate in online sperm donation. In a Skype interview lasting 45 to 75 minutes, we discussed their expectations, motivations and experiences as donors. </p>
<p>The men, aged 24 to 67, were from Australia, Canada, England, France, the Netherlands and the United States. The details of their experiences of donating sperm were unique and personal. However, certain common themes emerged.</p>
<p>Overwhelmingly, the men in our study viewed sperm donation as a way to help others.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/244172/original/file-20181106-74760-1lfhjba.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Each of the men in this research study had at least two donor children; one had up to 1,000 children.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>George is on a break from college and works a job at a warehouse. He hopes to eventually transition to another line of work that involves helping people. But for now, he’s making an impact during his off hours, meeting potential parents online and helping them conceive.</p>
<p>The online forum gave sperm donors a sense of control over the process. This enabled the donor to make the experience personal and meaningful.</p>
<p>Simon Watson, a donor from England, said: </p>
<blockquote>
<p>“When you help people privately it makes you feel like a person. You talk to someone on the phone and then you meet up.”</p>
</blockquote>
<p>Alex (not his real name) first began donating sperm about five years ago to help lesbian couples in Europe who were barred from accessing sperm banks. </p>
<blockquote>
<p>“At that time lesbians were somewhat marginalized… they didn’t have the right to get married and they didn’t have the right to access IVF (in vitro fertilization).”</p>
</blockquote>
<h2>Up to 1,000 donor children</h2>
<p>Procreation was a meaningful part of why men chose to donate sperm.</p>
<p>The men in our study each had at least two donor children. Simon Watson, who viewed donating sperm as a job, estimated that he had 500 to 1,000 donor children. </p>
<p>Donors like George saw sperm donation as a sort of plan B: It satisfied his urge to reproduce without the responsibilities of being a parent.</p>
<p>The men spoke about their involvement in decisions surrounding insemination.</p>
<p>Insemination occurs either naturally (through sexual intercourse) or artificially (using some variation of a cup and syringe). The men acknowledged that donors who advertise a preference for natural insemination were often viewed as predatory. For this reason, they all preferred the artificial method.</p>
<p>Men had complex and sometimes unresolved feelings about their attachment to their donor children. Alex said:</p>
<blockquote>
<p>“Even though I don’t consider myself their father I do consider that there’s a little part of me, and a little part of my family out there.”</p>
</blockquote>
<h2>Risk of disapproval</h2>
<p>Men accepted some risks in choosing to participate in online sperm donation. They had personal costs and inconveniences, for example, when meeting with the recipients. Men spoke about risking disapproval from others, including their family.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/244173/original/file-20181106-74760-tz7u5j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">All of the men interviewed preferred artificial insemination, to avoid being viewed as predatory.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Traditional sperm banks have strict requirements and protocols for donors, but online sperm donation is difficult to regulate and track, especially when donations occur across international borders. </p>
<p><a href="https://doi.org/10.1016/j.rbms.2017.02.001">Unclear or conflicting legal environments</a> may provide online sperm donors with a layer of protection. The men in our study said they were not concerned about the legal implications of donating sperm informally.</p>
<p>As societies bid farewell to the traditional sperm bank and increasingly turn online to find “the one,” we are confronted with important questions about the future of assisted reproduction and how to best protect the interests of everyone involved. </p>
<p>Moving forward, let’s be sure the answers to these questions reflect the many stories and experiences of online sperm donation.</p><img src="https://counter.theconversation.com/content/104754/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicole Bergen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sperm donation websites are the Ubers and Airbnbs of the fertility world. But why are they so popular? New research explains the reasons why some men donate.Nicole Bergen, PhD Candidate, L’Université d’Ottawa/University of OttawaLicensed as Creative Commons – attribution, no derivatives.