tag:theconversation.com,2011:/global/topics/testicles-27073/articlesTesticles – The Conversation2022-08-05T12:10:37Ztag: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">
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<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/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>
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<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>
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<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>
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<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>
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<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>
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<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/988842018-06-28T20:26:14Z2018-06-28T20:26:14ZDescended testicles: DNA study drops new hints on secrets of low hanging glands<figure><img src="https://images.theconversation.com/files/225176/original/file-20180627-112628-6lwhl4.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/rear-view-male-british-bulldog-standing-145264798?src=sMIjWZKN4Ka53dazPSbKjA-1-0">Shutterstock</a></span></figcaption></figure><p>The scrotum is a mystery. Why do most male mammals have their reproductive glands so vulnerably located in a sack of skin and muscle outside the body? According to new research, the answer might be found in those unusual mammals that have testicles located inside the abdomen. These includes elephants, aardvarks and others from a group that originated in Africa, <a href="http://www.pnas.org/content/98/1/1">known as the Afrotheria</a>.</p>
<p>Testicles function best when slightly <a href="http://rstb.royalsocietypublishing.org/content/364/1534/3341">below body temperature</a>. But we can’t say for sure this is why mammals evolved descended testicles, not least because males without scrota can still successfully reproduce. <a href="http://www.slate.com/articles/health_and_science/science/2013/07/are_testicles_external_for_cooling_galloping_display_or_something_else.html">External testes may also</a> be a way of showing off to potential mates, or to protect them from pressure inside the body created by movement. </p>
<p>The new study, <a href="https://dx.doi.org/10.1371/journal.pbio.2005293">published in PLOS Biology</a>, examined 71 placental mammals for two key genes – RXFP2 and INSL3 – that are needed for the development of <a href="https://nyaspubs.onlinelibrary.wiley.com/doi/full/10.1111/j.1749-6632.2009.03841.x">ligaments involved in testicular descent</a>. They found that in many afrotherian mammals without external testes these genes had mutated to the point where they would no longer function.</p>
<p>This data showed that the common ancestor of all afrotherian mammals, which may have lived <a href="https://academic.oup.com/gbe/article/8/2/330/2574016">70m to 90m years ago</a>, as well as the much older ancestor of all placental mammals, did have descended testicles. The research also showed this trait was reversed at least four separate times throughout the evolution of certain afrotherian animals. This suggests that studying Afrotheria and their ancestors in more detail might reveal exactly what the evolutionary advantages and disadvantages of having testes outside the body really are.</p>
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<figcaption>
<span class="caption">Balls in.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/african-bull-elephant-strolling-nonchalantly-down-576209782?src=E7U7l5WzdEGg8qMlCSZ0uQ-1-2">Shutterstock</a></span>
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<p>Scientists often try to work out what extinct animals were like and how they evolved, especially when there are no available fossils, by looking at their living descendants. If all the modern descendants of a particular species have a certain physical or behavioural trait, then it’s likely the ancestral species did too.</p>
<p>Reconstructing details of species like this is known as <a href="https://archosaurmusings.wordpress.com/2009/12/06/the-extant-phylogenetic-bracket/">extant phylogenetic bracketing</a>. But this approach relies on solid evidence for how groups of living species are related and, in the case of placental mammal groups, attempts to draw an accurate family tree are <a href="http://rstb.royalsocietypublishing.org/content/371/1699/20150140">still controversial</a>.</p>
<h2>Molecular fossils</h2>
<p>Studying the DNA of the Afrotheria gets around this problem because we don’t have to know how they are related more broadly to other placental mammal groups. Instead, the researchers looked for evidence of how the animals’ genes had changed as they evolved. They found that only modern afrotherian mammals had mutated versions of genes involved with testicular descent. All the other groups of mammals had these genes intact.</p>
<p>The fact that dysfunctional remnants of the RXFP2 and INSL3 genes are found in mammals without external testicles strongly suggests their ancestors had functioning copies of these genes. Over the course of evolution, when it was no longer an advantage to have external testes for whatever reason, mutations in these genes occurred without reducing the animal’s chances of reproduction. These mutated genes were then passed on to the next generation.</p>
<p>The researchers were also able to date roughly when these gene mutations occurred using what’s known as the molecular clock, the idea that gene mutations build up at specific rates. If you know what an original functioning gene looks like, you can work out how many mutations have occurred in mutated genes present in other animals. Using the molecular clock, you can then work out how long it would have taken for these mutations to build up.</p>
<p>What we still don’t know is why these mutations were successfully passed on and why the Afrotheria evolved so their testicles were no longer descended (testicondy). The researchers suggest that either testicondy is beneficial in some unknown way, that it results from another beneficial trait, or that it results from the constraints of some other bodily development.</p>
<p>Clearly much remains unknown and these ideas need testing. But what the latest study also shows is how scientists can use this form of <a href="https://www.sciencedirect.com/science/article/pii/S1871174X15000128?via%3Dihub">molecular palaeobiology</a> to work out what extinct organisms were like, even when we don’t have any hope of finding their complete physical remains as fossils.</p><img src="https://counter.theconversation.com/content/98884/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neil Adams 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>‘Molecular fossils’ in the DNA of elephants could help explain why their testicles are inside their bodies.Neil Adams, PhD candidate in Mammalian Palaeobiology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/783862017-05-26T02:41:26Z2017-05-26T02:41:26ZCodswallop: how to stop boxing deaths and brain injury with a simple rule<figure><img src="https://images.theconversation.com/files/171071/original/file-20170525-23232-fywpqm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If hitting below the belt, not the head, was the aim, then brain damage from boxing would disappear overnight.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/544977346?src=rFryrWFdcHig3OGjqdz6Wg-2-20&size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p>The <a href="http://www.abc.net.au/news/2017-05-19/david-browne-inquest-boxing-inspector-speaks-at-coronial-inquest/8542760">coronial inquest</a> in Sydney into the death by subdural haematoma (brain bleed) of 28-year-old boxer Davey Browne has yet again seen the same <a href="http://www.smh.com.au/sport/boxing/boxing-referee-not-trained-to-identify-serious-head-injury-davey-browne-inquest-20170524-gwbwdy.html">predictable response</a> about how we might prevent such outcomes in the future.</p>
<p>Solutions proposed by boxing officials, administrators and pundits are framed about when exactly a fight should be stopped, more even matching of boxers, greater latitude for trainers to throw in the towel and limiting pre-bout weight loss.</p>
<p>These solutions are as meaningful as if the Titanic’s owners had removed splinters from the liner’s handrails to reduce death and injury.</p>
<p>By 2015 there have been reportedly <a href="http://www.newyorker.com/news/sporting-scene/an-obsessive-chronicle-of-deaths-in-the-ring">2036 known boxing matches</a> where a competitor had died.</p>
<h2>What’s the point of boxing?</h2>
<p>In boxing, the main objective is to hit your opponent as directly and as hard as you can in the head, rendering them unconscious. The punch that knocks a boxer down so fast they can’t stand up within 10 seconds is what the crowds are baying for. It’s what pulls the crowds in and sees massive ticket prices for ringside seats in the hope of the glorious climax of a man being knocked out.</p>
<p>According to an <a href="http://www.medicaldaily.com/out-cold-what-happens-brain-when-we-get-knocked-out-331470">article</a> on what happens when boxers are knocked unconscious, a professional boxer’s punch can generate speeds of about 40-50 kilometres per hour.</p>
<p>The article continues, quoting research published in the journal <a href="http://www.neurology.org/content/70/10/771">Neurology</a>:</p>
<blockquote>
<p>A neurochemical reaction begins in the brain cells that cause cell death. The more cells that die, the fewer brain tissue you have … It may explain why people who suffer from head injuries are never quite the same afterward. </p>
</blockquote>
<h2>How common is this?</h2>
<p>We don’t have much <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2034695/">good quality data</a> about how commonly boxers suffer brain injury and later impairment. The few studies available don’t separate amateur and professional boxing. Professional boxing matches can last 12 rounds, while amateur matches last three. Amateurs also wear headgear, while professionals don’t.</p>
<p><a href="http://jamanetwork.com/journals/jama/article-abstract/417443">This study</a> of 30 professional boxers found the following range of impairment (from none to severe): 11 boxers were had normal brain function, with no signs of impairment, 12 had mild deficits, four were moderately impaired and three had signs of severe impairment. Boxers who had 12 or more professional bouts had significantly higher levels of brain injury.</p>
<h2>An obvious solution</h2>
<p>Fouls in boxing consist of hitting below the belt, holding, tripping, kicking, head butting, wrestling, biting, spitting on, or pushing your opponent.</p>
<p>If we reversed the rules on fouls to make a punch to the head a foul and a punch below the belt (aimed at the <a href="http://lingomash.com/slang-meanings/15660/slang-meaning-of-cods">cods</a> or testicles), a scoring shot, the brain injury problem would be resolved. Boxing might consider a change of name to “codswalloping”.</p>
<p>Every boy and man who has playing a body-contact sport has experienced the instantly sickening feeling being hit, kneed or bumped in their “<a href="http://www.cockneyrhymingslang.co.uk/slang/alternatives/210">orchestra stalls</a>”.</p>
<p>For those who have never had the experience, <a href="http://www.womenshealthmag.com/sex-and-love/getting-hit-in-the-balls">here</a> are five men’s eloquent accounts of the unforgettable, deeply imprinted sensation.</p>
<p>A blow to the head can cause concussion, brain injury and occasionally death. But a blow to the groin, while instantly and nauseatingly painful, may occasionally cause minor trauma that needs surgical correction, and infertility. Yet, it is extremely unlikely to cause major trauma or death.</p>
<p><a href="http://laws.worldrugby.org/?law=10&language=EN">Rugby union</a> and <a href="https://playnrl.com/referee/laws-of-the-game/">league</a> have long banned tackling around the head and head locking, and in <a href="http://www.afl.com.au/afl-hq/laws-of-the-game">AFL</a>, any contact with opponents’ heads is instantly penalised. Crowds get this. Yet in boxing, the crowd bays for the maximum risk of damage.</p>
<p>The spectacle of grown men trying to thump each other in the crotch would also have boundless comedic appeal. Evasive stepping and hip swivelling would emerge in those most adept at defensive codswalloping. Codswalloping with the Stars would be an instant TV viewing magnet.</p>
<p>The <a href="http://www.abc.net.au/news/2015-09-04/ama-calls-for-ban-on-boxing-at-olympics-commonwealth-games/6751424">Australian</a>, <a href="http://news.bbc.co.uk/2/hi/uk_news/87267.stm">British</a> and <a href="https://www.wma.net/policies-post/wma-statement-on-boxing/">World</a> medical associations have often called for boxing to be banned. Let’s get serious with boxing reform.</p>
<hr>
<p><em>This is Simon Chapman’s 100th article for The Conversation. His articles have been read more than 2.6 million times.</em></p><img src="https://counter.theconversation.com/content/78386/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>When he was about 12, Simon Chapman earned a few pounds in coins thrown into the ring as spectators watched him fight a friend at Jimmy Sharman's boxing tent at the Bathurst show in a preliminary, warm-up bout.</span></em></p>Forget tinkering with the rules of boxing. It’s time for a wholesale change. Let’s make hits to the groin the aim of the game and ban hits to the head.Simon Chapman, Emeritus Professor in Public Health, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/716522017-01-25T09:33:16Z2017-01-25T09:33:16ZWhy did humans evolve big penises but small testicles?<figure><img src="https://images.theconversation.com/files/154062/original/image-20170124-16062-gqpicb.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">POJ THEVEENUGUL / shutterstock</span></span></figcaption></figure><p>Humans have a much longer and wider penis than the other great apes. Even the largest of gorillas, more than twice as heavy as a human, will have a penis just two and half inches long when erect.</p>
<p>However our testicles are rather small. A chimpanzee’s testes weigh more than a third of its brain while ours weigh in at less than 3%. The relative size of our penis and testes is all down to our mating strategies, and can provide some surprising insights into early human culture.</p>
<p>Primates exhibit all sorts of mating behaviour, including monogamous, polygynous – where males have multiple mates – and multimale-multifemale. One indicator of which behaviour occurs in a species is the size difference between males and females. The greater this <a href="http://www.mnn.com/earth-matters/animals/blogs/9-most-dramatic-examples-sexual-dimorphism">sexual dimorphism</a>, the more likely the mating is either polygynous or multi-male to multi-female. This can be shown by observing chimpanzees and gorillas, our closest living relatives. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154053/original/image-20170124-16070-v8lwj1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Great ape sexual organs, compared for size (bonobos are flat chested until they get pregnant).</span>
<span class="attribution"><a class="source" href="https://global.oup.com/academic/product/the-cradle-of-humanity-9780198704522?cc=gb&lang=en&">Mark Maslin, The Cradle of Humanity</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Male chimpanzees are much larger than females, and they have a multi-male to multi-female mating system. Essentially, male chimps have sex all the time with any female and with any excuse. A female therefore may contain sperm from multiple partners at any one time, which puts the sperm itself – and not just the animals that produce it – into direct competition. For this reason, chimpanzees have evolved huge testicles in order to produce massive amounts of sperm, multiple times a day.</p>
<p>Male gorilla are also much larger than females, but they have a polygynous or harem-style mating system where many females live with a single male. With little or no competition actually inside the uterus, gorillas have had no need for a testicular arms race to facilitate the production of more and more sperm. Their testes, therefore, are relatively small. This is similar to modern humans, whose testes are also of very modest size and produce a relatively small amount of sperm. In fact human sperm count reduces by more than 80% if men ejaculate more than about two times a day.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154065/original/image-20170124-16066-5krmk7.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">Chimps have huge testicles for their size.</span>
<span class="attribution"><span class="source">Steffen Foerster / shutterstock</span></span>
</figcaption>
</figure>
<p>The human penis is large when compared with those of our closest relatives: chimpanzees, gorillas, and orangutans. However, primatologist <a href="https://www.researchgate.net/profile/Alan_Dixson">Alan Dixson</a> in his wonderfully detailed book, <a href="https://global.oup.com/academic/product/primate-sexuality-9780199544646?cc=gb&lang=en&">Primate Sexuality</a>, suggests that if we look at all primates, including monkeys, this is just wishful thinking. </p>
<p>Comparative measurements show the human penis is not exceptionally long. The Hamadryas baboon, for instance, a native of the Horn of Africa, has an erect penis that is <a href="https://www.youtube.com/watch?v=Da8KDkaRk8c&feature=youtu.be&t=3m40s">five and half inches long</a> – slightly shorter than an average human male, but they weigh only a third of our weight. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=828&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=828&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154055/original/image-20170124-16083-ai2ide.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=828&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some of the complex penises found in multi-male to multi-female mating primates such as chimpanzees (h), brown lemurs (a) or macaques (d, e, f).</span>
<span class="attribution"><a class="source" href="https://global.oup.com/academic/product/primate-sexuality-9780199676613?cc=gb&lang=en&">Alan F. Dixson, Primate Sexuality</a></span>
</figcaption>
</figure>
<p>The human penis is in fact extremely dull – it does not have lumps, ridges, flanges, kinks or any other exciting feature that other primates have. In primates, this lack of penis complexity is usually found <a href="https://global.oup.com/academic/product/primate-sexuality-9780199544646?cc=gb&lang=en&">in monogamous species</a>.</p>
<h2>Monogamy mystery</h2>
<p>This observation clashes with the fact that men are significantly larger than women. This suggests our evolutionary background involved a significant degree of polygynous, rather than exclusively monogamous, mating. This is supported by anthropological data showing that most modern human populations engage in polygynous marriage. Anthropologists Clellan Ford and Frank Beach in their book Patterns of Sexual Behaviour suggested that 84% of the 185 human cultures they had data on engaged in polygyny.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=866&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=866&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=866&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1088&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1088&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154056/original/image-20170124-16089-12sce5o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1088&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Primates with simpler penises tend to be monogamous like cotton top tamarins (a) or polygynous like gorillas (g).</span>
<span class="attribution"><a class="source" href="https://global.oup.com/academic/product/primate-sexuality-9780199676613?cc=gb&lang=en&">Alan F. Dixson, Primate Sexuality</a></span>
</figcaption>
</figure>
<p>However, even in these societies most people remain monogamous. Polygynous marriages are usually a privilege reserved only for high status or wealthy men. It is worth noting that hunter-gathers around the world practice only monogamy or serial-monogamy which suggests that our ancestors may have used this mating system. </p>
<p>At first sight, however, it would seem sensible for males to reproduce with as many females as possible. Human monogamy has long puzzled anthropologists, and lots of effort has gone in to working out what keeps males hanging around.</p>
<p>Three main theories have been put forward. First is the need for long-term parental care and teaching, as our children take a long time to mature. Second, males need to guard their female from other males. Third, our children are vulnerable for a long time and infanticide could be a risk from other males. So to ensure that children are able to reach maturity the male is likely to stay to protect them, both socially and physically. This may be why males have maintained their larger relative size.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154134/original/image-20170124-16074-893a23.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">Hamadryas baboons have unusually long penises.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Hamadryas_baboon.jpg">المُصوّر: مُعتز توفيق إغباريّة</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>If we view the evolution of monogamy mating systems in humans through the lens of human society it is clear that it takes a huge amount of social effort to maintain and protect more than one mate at a time. It is only when males have access to additional resources and power that they can protect multiple females, usually by ensuring other males protect them. So monogamy seems to be an adaptation to protect one’s mate and children from other males. This monogamy is reinforced by the high social cost and stress of attempting to do this for multiple partners, and it has become supported by cultural norms.</p>
<p>So when living in complex human societies the largest and most important sexual organ is the brain. Somewhere in our evolutionary past how smart and social we are became the major control on our access to sexual partners – not how big or fancy a male’s penis is.</p><img src="https://counter.theconversation.com/content/71652/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Maslin is a Professor at University College London, a Royal Society Industrial Fellow, Founding Director of Rezatec Ltd, Director of The London NERC Doctoral Training Partnership and a member of Cheltenham Science Festival Advisory Committee. He is an unpaid member of the Sopra-Steria CSR Board. He has received funding in the past from the NERC, EPSRC, ESRC, Royal Society, DIFD, DECC, BIS, FCO, Innovate UK, Carbon Trust, UK Space Agency, European Space Agency, Leverhulme Trust, WWF, JLT Re, Channel 4, RICS, British Council, and CAFOD.Prof. Maslin's latest book The Cradle of Humanity, published Oxford University Press, is out now.</span></em></p>We have the penis of a monogamous primate yet our body sizes suggest our ancestors slept around a lot.Mark Maslin, Professor of Palaeoclimatology, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/706362016-12-20T20:15:26Z2016-12-20T20:15:26ZWhy you can’t fry eggs (or testicles) with a cellphone<figure><img src="https://images.theconversation.com/files/151083/original/image-20161220-26741-nmhzbw.jpg?ixlib=rb-1.1.0&rect=721%2C0%2C3197%2C1982&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pocket your phone without worry.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic.mhtml?id=533966416">Phone image via www.shutterstock.com.</a></span></figcaption></figure><p>A minor craze in men’s underwear fashions these days seems to be <a href="http://www.nbcnews.com/news/world/boxer-shorts-claim-protect-testicles-cellphone-radiation-n538576">briefs that shield the genitals</a> from cellphone radiation. The sales claim is that these products protect the testicles from the harmful effects of the radio waves emitted by cellphones, and therefore help maintain a robust sperm count and high fertility. These undergarments may shield the testicles from radiation, but do <a href="http://www.newsweek.com/boxer-rebellion-pocketed-cellphone-may-be-behind-your-infertility-287075">male cellphone users really risk infertility</a>?</p>
<p>The notion that electromagnetic radiation in the radio frequency range can cause male sterility, either temporary or permanent, has been around for a long time. As I describe in my book <a href="http://press.princeton.edu/titles/10691.html">“Strange Glow: The Story of Radiation</a>,” during World War II some enlisted men would consistently and inexplicably volunteer for radar duty just prior to their scheduled leave days. It turned out that a rumor had been circulating that exposure to radio waves from the radar equipment produced temporary sterility, which the soldiers saw as an employment benefit.</p>
<p>The military wanted to know whether there was any substance to the sterility rumor. So they asked <a href="https://www.nobelprize.org/nobel_prizes/medicine/laureates/1946/muller-bio.html">Hermann Muller</a> – a geneticist who <a href="https://www.nobelprize.org/nobel_prizes/medicine/laureates/1946/muller-lecture.html">won the Nobel Prize</a> for showing that x-rays could cause sterility and genetic mutations – to evaluate the effects of radio waves in the same fruit fly experimental model he had used to show that x-rays impaired reproduction. </p>
<p>Muller could find no dose of radio waves that produced either sterility or genetic mutations, and concluded that radio waves did not present the same threat to fertility that x-rays did. Radio waves were different. But why? Aren’t both x-rays and radio waves <a href="http://www.livescience.com/38169-electromagnetism.html">electromagnetic radiation</a>?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=410&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=410&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151022/original/image-20161220-26741-1sutwex.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=410&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 electromagnetic spectrum, tiny wavelengths on the left, longer wavelengths on the right.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:EM_Spectrum_Properties_reflected.svg">Inductiveload</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Yes, they are – but they differ in one key factor: They have very different wavelengths. All electromagnetic radiation travels through space as invisible waves of energy. And it’s the specific wavelength of the radiation that determines all of its effects, both physical and biological. The shorter wavelengths carry higher amounts of energy than the longer wavelengths.</p>
<p>X-rays are able to damage cells and tissues precisely because their wavelengths are extremely short – one-millionth the width of a human hair – and thus are highly energetic and very harmful to cells. Radio waves, in contrast, carry little energy because their wavelengths are very long – about the length of a football field. Such long-wavelength radiations have really low energies – too low to damage cells. And it’s this big difference between the wavelengths of x-rays and radio waves that the infertility theorists fail to recognize.</p>
<p>X-rays, and other high-energy waves, produce sterility by killing off the testicular cells that make sperm – the “<a href="https://www.repropedia.org/spermatogonium">spermatogonia</a>.” And x-ray doses must be extremely high to kill enough cells to produce sterility. Still, even when the doses are high, the sterility effect is usually temporary because the surviving spermatogonia are able to <a href="http://doi.org/10.1002/aja.1001180211">spawn replacements</a> for their dead comrades, and sperm counts typically return to their normal levels within a few months.</p>
<p>So, if high doses of highly energetic x-rays are needed to kill enough cells to produce sterility, how can low doses of radio waves with energies too low to kill cells do it? Good question.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/axUBeF-W7II?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Don’t fall for the phone-cooking-egg hoax.</span></figcaption>
</figure>
<p>At this point you may be thinking that you’ve seen videos of <a href="https://www.youtube.com/watch?v=axUBeF-W7II">cellphones cooking eggs</a>. And you’ve even experienced your cellphone getting pretty warm when it’s used heavily. But this doesn’t show that cellphones put out a lot of radiation energy. The cooked egg video is a prank, and the phone gets hot because of the heat generated by the chemical reactions going on within the battery, not from radio waves.</p>
<p>Still you protest: What about those sporadic reports claiming that cellphones suppress sperm counts? For the moment, that’s all they are – sporadic reports, unconfirmed by other investigators. You can find all kinds of random assertions about the effects of radiation on health, both <a href="http://www.orau.org/ptp/collection/quackcures/quackcures.htm">good</a> and <a href="https://www.scribd.com/document/59721111/TOP10-Myths-About-Radiation">bad</a>, most of which imply that there is some type of validated scientific evidence to support the claim. Why not believe all of them?</p>
<p>If we’ve learned anything over the years about scientific evidence, it’s that isolated findings from individual labs, reporting limited experimental data, do not a strong case make. Most of the very limited “scientific” reports of infertility caused by cellphones, often <a href="http://www.ewg.org/cell-phone-radiation-damages-sperm-studies-find">cited by anti-cellphone activists</a>, come from outside the radiation biology community, and are published in lower-tier journals of questionable quality. Few, if any, of these reports make any attempt at actually measuring the radiation doses received from the cellphones (probably because they lack either the expertise or the equipment required to do it).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151040/original/image-20161220-26748-1ive95i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Human sperm, unconcerned by what’s in your pocket.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Sperm_(265_33)_human.jpg">Doc. RNDr. Josef Reischig, CSc.</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>And none actually measure fertility rates – the health endpoint of concern – but rather measure sperm counts and other sperm quality parameters and then infer that there will be an impact on fertility. In fact, sperm counts can vary widely between normally fertile individuals and even within the same individual from day to day. For example, men who frequently ejaculate have lower sperm counts, as you might expect, because they are regularly jettisoning sperm. (Men who ejaculate daily can have <a href="http://doi.org/10.1186/s12958-015-0045-9">sperm counts 50 percent lower</a> than men who don’t.) Perhaps the allegedly lower sperm counts of cellphone users just means that they are having more sex!</p>
<p>But seriously, the point is this: There are so many things that can affect sperm counts in big ways that minor fluctuations in sperm counts have no practical impact on whether a man will produce babies, even if it were true that cellphones can modestly suppress sperm counts.</p>
<p>It is clear that these infertility claims are not the consensus of the mainstream scientific community – a community that demands more rigorous evidence. There are many excellent laboratories around the world that study radiation effects, and it isn’t difficult to study infertility in fruit flies, mice and even people. (It’s fairly easy to find men willing to <a href="https://verdict.justia.com/2012/01/24/men-who-give-it-away">donate sperm samples</a>.) If the sterility story were true, there would be a chorus of well-respected laboratories from around the world singing the cellphone infertility song, not just a few.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=666&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=666&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=666&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=837&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=837&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151036/original/image-20161220-26748-eadyou.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=837&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Guglielmo Marconi, inventor of the radio.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/smithsonian/2551824648">Smithsonian Institution</a></span>
</figcaption>
</figure>
<p>The fact is, the current data suggesting that cellphones cause infertility are too weak to challenge the dogma of over 100 years of commercial experience with radio waves. Radio waves are not unique to cellphones. They have been used for telecommunication ever since <a href="http://www.history.com/this-day-in-history/marconi-sends-first-atlantic-wireless-transmission">Marconi first demonstrated in 1901</a> that they could carry messages across the entire Atlantic Ocean. Early radio workers received massive doses of radio waves, yet there is no indication they had any problems with their fertility. If they didn’t experience fertility problems with their high doses, how can the relatively low doses from cellphones have such an effect? Hard to understand.</p>
<p>Nevertheless, people can spend their money as they please and wear any underwear they want. But if you are still concerned about radio waves affecting your fertility, why not just carry your cellphone in your shirt pocket rather than your pants, and let your testicles be?</p><img src="https://counter.theconversation.com/content/70636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Timothy J. Jorgensen does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Did your holiday gift list include radiation-shielding undies to protect your privates from cellphone radio waves? A radiation expert explains they’re unnecessary – your phone won’t affect your fertility.Timothy J. Jorgensen, Director of the Health Physics and Radiation Protection Graduate Program and Associate Professor of Radiation Medicine, Georgetown UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/574882016-05-04T20:17:56Z2016-05-04T20:17:56ZKlinefelter’s syndrome: being unable to produce testosterone has serious implications for men<figure><img src="https://images.theconversation.com/files/121123/original/image-20160504-19860-1hxmuv.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most men don't know the normal size of testes. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This is part of our series on hidden or stigmatised health conditions in men. Read the other articles in the series <a href="https://theconversation.com/au/topics/mens-hidden-health-conditions">here</a>.</em></p>
<hr>
<p>Klinefelter’s syndrome is a genetic disorder that affects approximately <a href="http://www.ncbi.nlm.nih.gov/pubmed/21449864">one in 450 males</a>. Each cell in the human body has 23 pairs of chromosomes. The sex chromosomes in a female are XX, and XY in men. Typically, men have 46 chromosomes with an arrangement of 46XY, while those with Klinefelter’s syndrome have a 47XXY arrangement.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119059/original/image-20160418-23612-2pabxf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&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 chromosomal arrangement in someone with Klinefelter’s.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>Klinefelter’s syndrome is not commonly diagnosed, with only <a href="http://www.ncbi.nlm.nih.gov/pubmed/21449864">four in 10 men</a> diagnosed after birth and <a href="http://www.ncbi.nlm.nih.gov/pubmed/12574191">10% diagnosed pre-puberty</a>. Klinefelter’s syndrome is not typically diagnosed at birth, although physical characteristics may include a small penis and undescended testicles. </p>
<p>Klinefelter’s syndrome is the most common form of <a href="http://www.mayoclinic.org/diseases-conditions/male-hypogonadism/basics/definition/con-20014235">hypogonadism</a>, where men are unable to produce sperm or sufficient levels of the male sex hormone, testosterone. The low levels of testosterone result in the underdevelopment of typical male characteristics. </p>
<p><a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/klinefelter-syndrome">Symptoms of Klinefelter’s syndrome</a> vary between individuals, but typically include small testicles, lack of facial, pubic and underarm hair, gynaecomastia (breast tissue enlargement), poor muscle development, disproportionately long arms and legs (compared to the body), and potential learning and language difficulties. </p>
<p>As adults, men with Klinefelter’s syndrome are infertile, as the extra X chromosome affects the ability to produce sperm, known as <a href="https://www.andrologyaustralia.org/your-health/klinefelters-syndrome/">azoospermia</a>. Men with this condition may also experience a low libido, depression and are at risk of osteoporosis. </p>
<h2>Causes</h2>
<p>While Klinefelter’s syndrome is a genetic disorder, it is not one that is inherited, as <a href="https://www.andrologyaustralia.org/your-health/klinefelters-syndrome/">brothers</a> of men with Klinefelter’s syndrome typically have the 46XY pattern. </p>
<p>The addition of the extra X chromosome is believed to occur as a <a href="https://ghr.nlm.nih.gov/condition/klinefelter-syndrome">random event</a> during the formation of the reproductive cells, either within the fertilised egg or during cell division as the baby develops. </p>
<h2>Diagnosis</h2>
<p>Klinefelter’s syndrome can be diagnosed through a variety of tests. Physical examination of the genitals will confirm the size of the testes, with the size typically <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1686046/">less than four millilitres</a> (the size of a sultana grape). </p>
<p>Klinefelter’s syndrome can be confirmed using a blood test, which involves chromosomal analysis. Further blood tests can also examine the levels of testosterone (and other sex hormones), as well as semen examination for levels of sperm. Klinefelter’s syndrome may also be diagnosed prenatally, through maternal blood testing.</p>
<h2>Treatment</h2>
<p>Men diagnosed with Klinefelter’s syndrome cannot be cured; rather treatment aims to overcome some aspects of the symptoms. Hormone therapy, specifically testosterone replacement, is a lifelong therapy that increases physical strength, body tone and general wellbeing in men. </p>
<p>Testosterone therapy is available in various formats including gels, injections, lotions, creams and patches. If diagnosis occurs during the teenage years, testosterone therapy is initiated at a low dose and increased through the adult years. </p>
<p>In some men with Klinefelter’s syndrome, sperm may be found in the testicular tissue. For such men, assisted reproductive therapies such as intracytoplasmic sperm injection (<a href="http://www.ivf.com.au/fertility-treatment/icsi-treatment#what-is-icsi-">ICSI</a>) may be used to achieve pregnancy with their partners. ICSI is a form of in vitro fertilisation (<a href="http://www.ivf.com.au/fertility-treatment/ivf-treatment">IVF</a>) whereby a single sperm is injected into each egg during the IVF procedure. </p>
<p>Donor insemination and adoption are alternatives in cases where assisted reproductive therapies are not an option. </p>
<p>Cosmetic surgery may be performed to remove the enlarged breast tissue. Counselling, physical and speech therapy may also be performed to assist men with the psychosocial aspects of the diagnosis. </p>
<h2>Why is it hidden?</h2>
<p>Lack of knowledge, awareness and psychosocial impact are all reasons Klinefelter’s syndrome is typically underdiagnosed. Men typically use <a href="http://www.ncbi.nlm.nih.gov/pubmed/16411874">health services</a> less frequently <a href="http://theconversation.com/men-more-reluctant-to-go-to-the-doctor-and-its-putting-them-at-risk-57420">than women</a>. Even when men do see a doctor, a reproductive health examination is not routinely performed.</p>
<p>Few men have ever heard of Klinefelter’s syndrome, and similarly would be unaware of the symptoms. For example, many men would not know what the typical size of the testes is, and so may be unaware they have small testes. </p>
<p>In teenagers, symptoms of Klinefelter’s syndrome may be clouded by learning problems and the onset of puberty, with Klinefelter’s syndrome not primary in the thoughts of many health professionals. Embarrassment, stoicism and fear of the unknown are common psychosocial issues perceived by men that prevent them from seeing their doctor about reproductive health issues. </p>
<p>Treatment and management strategies for Klinefelter’s syndrome can ensure men diagnosed with the condition have good health outcomes. Further engagement with Klinefelter’s syndrome support groups can provide men with peer support and assist in overcoming any perceived psychosocial barriers associated with its diagnosis.</p>
<hr>
<p><em>Further reading:</em></p>
<p><em><a href="http://theconversation.com/dads-get-postnatal-depression-too-55829">Dads get postnatal depression too</a></em></p>
<p><em><a href="http://theconversation.com/men-more-reluctant-to-go-to-the-doctor-and-its-putting-them-at-risk-57420">Men more reluctant to go to the doctor - and it’s putting them at risk</a></em></p>
<p><a href="https://theconversation.com/breast-cancer-campaigns-might-be-pink-but-men-get-it-too-56663"><em>Breast cancer campaigns might be pink, but men get it too</em></a></p>
<p><em><a href="https://theconversation.com/hows-your-walnut-mate-why-men-dont-like-to-talk-about-their-enlarged-prostate-58209">How’s your walnut, mate? Why men don’t like to talk about their enlarged prostate</a></em></p>
<hr>
<p><em>Correction: the chromosomal arrangement has been corrected to say 47XXY</em></p><img src="https://counter.theconversation.com/content/57488/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dragan Ilic 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>Men with Klinefelter’s syndrome are infertile, as the extra X chromosome affects the ability to produce sperm.Dragan Ilic, Associate Professor, Department of Epidemiology and Preventive Medicine, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.