tag:theconversation.com,2011:/fr/topics/whats-the-point-of-sex-34407/articlesWhat's the point of sex – The Conversation2017-01-17T19:05:55Ztag:theconversation.com,2011:article/678492017-01-17T19:05:55Z2017-01-17T19:05:55ZWhat’s the point of sex? It frames gender expression and identity – or does it?<figure><img src="https://images.theconversation.com/files/149148/original/image-20161208-18053-1vg3kn9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Social definitions of sex tend to oversimplify the biological determinants of gender and anatomy. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/renawgraphy/3701425567/in/photolist-6D5LSc-7m1xii-dhM8W-dRZUsP-dS6uv9-q785-4vYnD-9xYYmG-f3xJxH-aX2H1e-22nqk-22nkF-22nC7-6DjPvK-6dejZy-f3xJtn-22nMB-22noF-77B4F4-aX2Hfa-dADrDC-ffMAq7-3iiSAn-4R1sS-cSPRrh-22nUJ-8bfEkd-g4PzPN-22nSS-22nj4-22nFd-22nrt-q78a-7ULrja-22nmQ-56wkif-77B38H-22nDj-7ULrBB-f62U-9eN2X7-9eN3eG-77B1Fi-22nPD-3DgYv-3Fk9jc-aer7ZX-3FprUm-fmsfQd-a5A5uQ">renawgraphy/flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em>The act of penetrative sex has evolved over millions of years as a mechanism to deliver sperm to eggs and initiate pregnancy. But there’s more to sex than just the meeting of two sets of genes. The ‘What’s the point of sex?’ series examines biological, physical and social aspects of sex and gender.</em></p>
<p><em>Today’s piece looks at sexual identity and gender, and how these are expressed in a social context.</em> </p>
<hr>
<p>Comedian <a href="http://www.russellbrand.com/">Russell Brand</a> recently sparked a flurry of excitement in the media when speaking about his impending fatherhood. He revealed in an <a href="https://www.youtube.com/watch?v=5UalDTd6O3M">interview</a> with Jonathon Ross that he and his partner, Laura Gallacher, were considering raising their child “<a href="https://en.wikipedia.org/wiki/Gender_neutrality">gender-neutral</a>”. He said:</p>
<blockquote>
<p>We don’t know the gender and I may not even ever impose a gender upon it, let the child grow up and be whatever the hell it is, never tell it there is such a concept.</p>
</blockquote>
<p>Russell Brand is a colourful character: a comedian, social entrepreneur, commentator and media personality with a well-documented history of <a href="https://www.theguardian.com/books/2007/nov/12/biography.mikeleigh">sex</a> and <a href="https://www.theguardian.com/culture/2013/mar/09/russell-brand-life-without-drugs">drug</a> addiction. Given his exuberant personality and flamboyant approach to life, he was never likely to take a conventional approach to parenting. </p>
<p>But what does it mean to raise a child “gender neutral” and why has his flippant comment generated such a range of views from <a href="http://www.irishtimes.com/life-and-style/people/russell-brand-s-genderless-daughter-not-one-of-his-better-ideas-1.2872246">ridicule</a> to <a href="http://m.huffpost.com/uk/entry/12926202">praise</a>?</p>
<h2>What are you having, pink or blue?</h2>
<p>It’s no surprise Russell Brand was asked about the sex of his soon-to-be-born child. It is a topic frequently discussed with expectant parents, who now have the option to find out whether they are expecting a boy or a girl, and may choose to keep the secret until the baby is born or disclose the information to others. Gender reveal parties have even become a <a href="http://www.cosmopolitan.com/lifestyle/a44292/baby-gender-reveal-stupid/">thing</a>.</p>
<p>The terms “<a href="https://en.wikipedia.org/wiki/Sex">sex</a>” and “<a href="https://en.wikipedia.org/wiki/Gender">gender</a>” are often used interchangeably in casual conversation. Although there are many ideas about how terms should be used most correctly, in general the idea of gender refers to the way that biological sex is understood and expressed in society. Characteristics a society determines to be more “masculine” or “feminine” may be called “<a href="https://en.wikipedia.org/wiki/Gender_role">gender roles</a>”. </p>
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<p><em>Russell Brand talking with Jonathon Ross about the gender of his first child.</em></p>
<p>Of course there is wide variability in the way masculinity and femininity are expressed by different people, at different times in history and across different cultures. </p>
<p>Gender neutrality is the idea social institutions, policies and language should avoid assigning roles based on sex or gender. The desire not to constrain a child by the social expectations associated with sex and gender <a href="http://everydayfeminism.com/2013/01/gender-neutral-parenting-myths/">underpins</a> gender neutral parenting. </p>
<p>This approach does not attempt to ignore or abolish the notion of sex or gender, but rather avoids forcing preconceived expectations on a child on the basis of their sex or gender. It does not push a child toward the expression of any particular gender identity. </p>
<p>Rather, it comes from a desire to raise a child with the freedom to develop an individual identity without being constrained by expectations about how a boy or girl is meant to behave, act or be.</p>
<h2>‘Sex’ comes from more than just chromosomes</h2>
<p>A person’s sex is usually considered to be related to biology. At the simplest level it is defined as whether a person is male or female on the basis of the <a href="https://www.britannica.com/science/sex-chromosome">presence or absence of a Y chromosome</a>: males carry XY chromosomes and females carry XX chromosomes. That sounds simple, yes?</p>
<p>But it’s not! Sex is a lot more complex than genetics or even genitals. There is no single or simple marker that defines a person as clearly male or female. This supposedly simple binary concept is really a complex combination of genetic, hormonal and developmental processes that aligns people more closely with one sex or another, and these markers may be mismatched. </p>
<p>As a recent <a href="http://www.nature.com/news/sex-redefined-1.16943">paper</a> in the respected scientific journal Nature stated:</p>
<blockquote>
<p>New technologies in DNA sequencing and cell biology are revealing that almost everyone is, to varying degrees, a patchwork of genetically distinct cells, some with a sex that might not match that of the rest of their body.</p>
</blockquote>
<p>There are many examples of differences in sex development that may affect chromosomes, gonads and/or genitals. The range and nature of such intersex differences is extensive, and <a href="http://www.nature.com/nrendo/journal/v10/n10/full/nrendo.2014.130.html">may affect up to one in 100 people</a>. </p>
<p>Scientific discoveries about the range of “sex” and the social implications of this diversity are now becoming better known, and are also made visible through the advocacy of people who identify as intersex. </p>
<p>As they tell their stories we can <a href="https://www.bookdepository.com/Intersex-Tiffany-Jones/9781783742080">better understand</a> how to modify our social and legal structures to better and more meaningfully accommodate the biological realities of sex. </p>
<p>However, it is still the case <a href="http://www.nature.com/news/sex-redefined-1.16943">that</a>: </p>
<blockquote>
<p>These discoveries do not sit well in a world in which sex is still defined in binary terms. Few legal systems allow for any ambiguity in biological sex, and a person’s legal rights and social status can be heavily influenced by whether their birth certificate says male or female.</p>
</blockquote>
<h2>Times are changing, slowly</h2>
<p>The concept that sex is not simply a case of “male” and “female” is <a href="http://qz.com/807743/conservatives-have-created-a-fake-ideology-to-combat-the-global-movement-for-lgbti-rights/">strongly resisted</a> in some quarters despite the scientific evidence, and sadly, people who challenge the binary notion of sex are often the target of <a href="http://www.npr.org/sections/thetwo-way/2016/11/14/502036699/hate-crimes-rose-in-2015-with-religious-bias-a-growing-motivation-fbi-data-shows">hate crimes</a> and <a href="http://www.tandfonline.com/doi/abs/10.1080/00049182.2016.1248751">abuse</a>.</p>
<p>Nevertheless, changes are being made to more accurately reflect reality. For example, the most recent Australian census <a href="http://www.sbs.com.au/news/article/2016/07/20/australian-census-offer-other-option-gender-question">offered an “other” box</a> for those who do not identify as either male or female, and Canada now <a href="http://www.cbc.ca/news/politics/gender-neutral-trudeau-passport-travel-identification-male-female-1.3835344">offers the same options</a> for passports. Gender neutral toilets are also <a href="http://www.smh.com.au/comment/gender-neutral-public-toilets-should-be-the-norm-20160503-golmtp.html">becoming more common</a>.</p>
<p>After all the anticipation of Russell Brand’s impending fatherhood, his child was <a href="http://www.hellomagazine.com/healthandbeauty/mother-and-baby/2016110934520/russell-brand-baby-name-gender-revealed/">born in November</a> and appears to be a girl who has been named Mabel. It remains to be seen how her parents will embrace the challenges of parenting, and how our society will continue to embrace the ongoing challenges of redefining sex.</p><img src="https://counter.theconversation.com/content/67849/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jayne Lucke is the Director of the Australian Research Centre in Sex, Health and Society at La Trobe University. The Australian Research Centre in Sex, Health and Society receives funding from diverse sources listed in the annual report available from the website: <a href="http://www.latrobe.edu.au/arcshs">http://www.latrobe.edu.au/arcshs</a>. </span></em></p>When his partner was pregnant, Russell Brand announced he may raise the child ‘gender-neutral’ to avoid social constraints associated with being a boy or a girl. So what determines your ‘sex’?Jayne Lucke, Professor & Director of the Australian Research Centre in Sex, Health & Society, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/678482017-01-16T19:04:34Z2017-01-16T19:04:34ZWhat’s the point of sex? It’s good for your physical, social and mental health<figure><img src="https://images.theconversation.com/files/147523/original/image-20161125-15333-iap5ja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Committing to a safe and active sex life could boost your health in 2017. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/pedrosimoes7/11562633354/in/photolist-iBKw4u-acQgaW-iRxj4-d8BzHu-74iSqD-nYUTEh-4HMZfG-9pLAqE-moaiYQ-a9rLX3-9pnw9W-mnjaKd-oaSNq4-5LNL8c-aj5ZVm-799RG6-d9QSMP-e8UZqM-dxMzwv-nrsDnA-9XNgBv-qpjQ1M-9sa2bM-atYo2W-cGs8eU-71MPTV-Gpsn6-8pxx7a-dCZLDy-gfYqPZ-f8y7BF-Hxi4P-9XRadb-qTHA6y-76j7Ez-9XNh3B-dxF2HR-jidSJR-pGNS6B-qev26T-6xNn2m-r6ZNVg-BuuPkZ-5RY94L-2EK52b-dsqYgA-6WgMUj-961sqp-9LD7XT-ca3bHj">pedrosimoes7/flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p><em>The act of penetrative sex has evolved over millions of years as a mechanism to deliver sperm to eggs and initiate pregnancy. But there’s more to sex than just the meeting of two sets of genes. The ‘What’s the point of sex?’ series examines biological, physical and social aspects of sex and gender.</em></p>
<p><em>Today’s piece describes physical, social and mental health benefits that are a consequence of consenting sexual relationships, or the pursuit of them.</em> </p>
<hr>
<p>Whether you talk about it in polite society or not, sex is central to who you are as a person. In fact, we are all here as a result of meaningful looks, snatched moments, sweaty palms, clumsy first touches, tangled limbs and orgasms. </p>
<p>Were sex only important for procreation, it would more than do its job from an evolutionary perspective. However, evidence suggests that at a physical and social level, sex is about much more than making babies. </p>
<p>Most nonhuman animals have no interest in sex outside of a reproductive context. But women have sex throughout their menstrual cycle despite being fertile for only a few days each month, and go on having sex long after menopause renders them infertile. And of course, couples who are of the same sex, using contraception or infertile are no less keen for congress than any pregnancy-focused counterparts. </p>
<p>Ultimately, no one knows for sure what the point of all this sex is, but its other biological effects may provide clues.</p>
<h2>Sex brings people together</h2>
<p>Have you ever met someone who is right for you “on paper”, but when push comes to shove their scent seems wrong, or the spark isn’t there? Our bodies can tell our minds who we don’t want to be with. Similarly, our bodies can give us strong signals about whether we want to stay close to somebody. </p>
<p>When we touch, kiss and have sex, our body responds with a release of hormones linked to bonding. Most important among these appear to be <a href="http://science.sciencemag.org/content/322/5903/900">oxytocin and vasopressin</a>. </p>
<p>Such releases are particularly marked during sexual excitement and <a href="https://www.ncbi.nlm.nih.gov/pubmed/8135652">orgasm</a>. The release of these chemicals is thought to promote love and commitment between couples and increase the chance that they stay together. </p>
<p>Some research supporting this comes from studies of rodents. For example, female voles (sturdy little mouse-type creatures) have been found to bond to male voles when their copulation with them is paired with an <a href="https://www.ncbi.nlm.nih.gov/pubmed/7576222">infusion of oxytocin</a>. </p>
<p>In humans, those couples who have sex less frequently are at <a href="https://asu.pure.elsevier.com/en/publications/sexual-frequency-and-the-stability-of-marital-and-cohabiting-unio">greater risk of relationship dissolution</a> than are friskier couples.</p>
<p>But oxytocin is not just good for pair bonding. It is released from the brain into the blood stream in many social situations, including <a href="http://www.pnas.org/content/93/21/11699.short">breastfeeding</a>, <a href="http://link.springer.com/article/10.1007/BF02734261">singing</a> and most activities that involve being “<a href="http://www.sciencedirect.com/science/article/pii/S0018506X12000098">together</a>” pleasurably. It appears oxytocin plays a role in a lot of group oriented and socially harmonious activities, and is <a href="https://www.ncbi.nlm.nih.gov/pubmed/20538951">implicated in altruism</a>. </p>
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<a href="https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=487&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=487&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=487&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=611&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=611&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149808/original/image-20161213-1608-190gcc8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=611&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">Bonobos resolve conflicts through sexual activities.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/47847725@N04/4530706679/in/photolist-7Un4fp-HLd7Xr-faSiri-bipnKv-9xMeMS-9xJhJr-6dA1un-9xMcfm-9tbBYN-9xJfHR-FqGeFS-2Wqso9-9xMcow-9xMdAw-5gDs7r-9xMemq-pUt8Tz-9xMeB9-9xJh1R-e7351q-9xMcKw-e7369o-bipnEi-koShwD-2Wm2Ma-9xJdQK-9xMcbd-9x2vFB-8K5CXP-9xJg1e-DTjuhc-2Wm2K6-9xMeoC-e735sj-eg2WvM-fEiC3z-mgKicU-4femKm-6WP6n4-hTmvw6-6WP6Ec-nNEHrU-GwmstG-bUmKZ9-bUPypJ-sq6Hyw-9xJhpF-9xMf4E-9xMcmY-jXAybe">LaggedOnUser/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Bonobos (a species of great ape) appear to take full advantage of the link between harmony and sex, often <a href="http://onlinelibrary.wiley.com/doi/10.1002/ajp.20000/abstract">resolving conflicts or comforting one another</a> by rubbing genitals, copulating, masturbating or performing oral sex on one another. This isn’t something to try during a tense board meeting, but such findings hint at the potential role lovemaking may play in reconciliation between couples. </p>
<h2>Sex is a healthy activity</h2>
<p>Sex is a form of <a href="http://jamanetwork.com/journals/jamainternalmedicine/article-abstract/604787">exercise</a>: a fun <a href="http://www.sexcalculator.co.uk/">online calculator</a> can help you calculate how much energy you burned during your last sex session. </p>
<p>People with <a href="http://jamanetwork.com/journals/jama/fullarticle/188762">poor physical or emotional health</a> are also more likely to have sexual problems. Here causality is hard to establish – healthier people will tend to be “up” for more sex, but it is also likely that the physical workout and bonding benefits conferred by satisfying sex lead to healthier, happier lives. </p>
<p>It’s also possible our long, energetic and physically demanding style of sex evolved to help us appraise the health of potential long-term partners. </p>
<h2>Sex can make us creative</h2>
<p>Some theorists propose art forms such as <a href="http://www.counter-currents.com/2010/12/darwins-other-idea-geoffrey-millers-the-mating-mind/">literature, music</a> and <a href="https://asu.pure.elsevier.com/en/publications/peacocks-picasso-and-parental-investment-the-effects-of-romantic-">painting</a> result from our drive to get people in bed with us. </p>
<p>In a society in which there’s at least some choice available in whom we mate with, competition will be fierce. Consequently, we need to display characteristics that will make us attractive to those we are attracted to. </p>
<p>In humans, this is thought to result in competitive and creative displays, as well as displays of <a href="https://books.google.com.au/books?id=cEDVUT4TvYcC&redir_esc=y">humour</a>. We certainly see evidence of the success of this tactic: musicians, for example, are stereotyped as never lacking a potential mate. Picasso’s most productive and creative periods usually coincided with the <a href="https://asu.pure.elsevier.com/en/publications/peacocks-picasso-and-parental-investment-the-effects-of-romantic-">appearance of a new mistress</a> on the scene. </p>
<h2>Science says: go for it</h2>
<p>What then does science tell us? Simply put, non-reproductive sex is an activity that can bring biological rewards. It can bring people together, help drive creative endeavours, and contribute to good health.</p><img src="https://counter.theconversation.com/content/67848/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fiona Kate Barlow receives funding from The Australian Research Council. </span></em></p><p class="fine-print"><em><span>Brendan Zietsch receives funding from The Australian Research Council. </span></em></p>An active sex life can promote love and togetherness, drive creativity and build better health.Fiona Kate Barlow, Senior Research Fellow, The University of QueenslandBrendan Zietsch, Research Fellow, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/678472017-01-15T19:02:15Z2017-01-15T19:02:15ZWhat’s the point of sex? It’s communication at a biological level<figure><img src="https://images.theconversation.com/files/150642/original/image-20161219-26097-gc4mgx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sex is a form of biological communication, and women use it to make decisions on whether to invest in a pregnancy. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/532126837?src=pQ1kr9N-uQLD_ez8OB_3gw-5-84&id=532126837&size=huge_jpg">from www.shutterstock.com </a></span></figcaption></figure><p><em>The act of penetrative sex has evolved over millions of years as a mechanism to deliver sperm to eggs and initiate pregnancy. But there’s more to sex than just the meeting of two sets of genes. The ‘What’s the point of sex?’ series examines biological, physical and social aspects of sex and gender.</em></p>
<p><em>Today’s piece looks at how a woman’s immune system responds to sexual intercourse and facilitates healthy pregnancy.</em> </p>
<hr>
<p>Most people think just one sperm is needed to fertilise a woman’s egg and make a healthy pregnancy. This underpins a common view that all the other sperm – and all the other sex – are surplus to requirements, at least when it comes to conceiving a pregnancy. </p>
<p>However, biologists now believe sexual intercourse is not just a sperm delivery process, but also a kind of biological communication. Regardless of whether fertilisation occurs, sperm and other components of the ejaculated fluid trigger subtle changes in the immune system of women. </p>
<p>This has consequences for pregnancy should it happen later. More broadly, the importance of regular sexual activity also has implications for fertility planning, and for IVF and other forms of assisted reproduction, which generally do not take sexual practice or history into account. </p>
<h2>Sperm swim in a soup of molecular messages</h2>
<p>Evidence from <a href="https://www.ncbi.nlm.nih.gov/pubmed/26178848">animal research</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/27485480">clinical studies</a> has led researchers to conclude seminal fluid – the fluid sperm are bathed in following ejaculation – plays an important role in fertility. </p>
<p>Seminal fluid <a href="https://www.ncbi.nlm.nih.gov/pubmed/27485480">contains small molecules</a> that act as biological signals. Once deposited in the vagina and the cervix of a woman, these <a href="https://www.ncbi.nlm.nih.gov/pubmed/23480148">persuade the woman’s immune system</a> to adopt a profile that tolerates (that is, recognises and accepts) sperm proteins known as “transplantation antigens”. </p>
<p>The tolerant profile matters if fertilisation takes place. Immune cells <a href="https://www.ncbi.nlm.nih.gov/pubmed/19631389">recognise the same transplantation antigens</a> on the developing baby, and so support the process through which the embryo implants into the wall of the uterus and forms a healthy placenta and fetus.</p>
<p>So over time, repeated contact with the same male partner acts to <a href="http://esa-srb-2013.m.asnevents.com.au/schedule/session/1518/abstract/7382">stimulate and strengthen</a> a tolerant immune response to his transplantation antigens. The immune system of a woman responds to her partner’s seminal fluid to progressively build the chances of creating a healthy pregnancy over at least several months of regular sex. </p>
<p>Some forms of infertility and disorders of pregnancy are caused by immune rejection, when the process of tolerance is <a href="https://www.ncbi.nlm.nih.gov/pubmed/25023687">not adequately established</a>. </p>
<h2>Healthier pregnancy after months of sex</h2>
<p>A condition known as preeclampsia provides useful insights into how exposure to seminal fluid influences the success of pregnancy. <a href="https://www.betterhealth.vic.gov.au/health/healthyliving/pregnancy-pre-eclampsia">Preeclampsia</a> is an inflammatory disorder of pregnancy that compromises growth of the fetus, and often causes prematurity in babies. It can be life-threatening for mothers if left untreated. </p>
<p>Preeclampsia is more common when there has been limited sexual contact with the father before pregnancy is conceived, and is associated with <a href="https://www.ncbi.nlm.nih.gov/pubmed/20331588">insufficient establishment</a> of immune tolerance in the mother. </p>
<p>The length of time a couple have had a sexual relationship seems more important than the frequency of intercourse. In a <a href="https://www.ncbi.nlm.nih.gov/pubmed/19679359">study</a> of first pregnancies in 2507 Australian women, around 5% developed preeclampsia. Affected women were more than twice as likely to have had a short sexual relationship (less than six months) compared to the women who had healthy pregnancies. </p>
<p>Women with less than three months sexual activity with the conceiving partner had a 13% chance of preeclampsia, more than double the average occurrence. Among the few women who conceived on the first sexual contact with the father, the chance of preeclampsia was 22%, three times higher than the average. Low birth weight babies were also more common in this group. </p>
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<img alt="" src="https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151359/original/image-20161222-17312-1f7bfqo.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">
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<span class="caption">Sperm swim in a soup of molecules that trigger an immune response in women.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/474203128?src=IWpjS5pr2oAjBHIBhebTIw-2-52&id=474203128&size=vector_eps">from www.shutterstock.com</a></span>
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<p>No relationship is observed between frequency of sexual activity during pregnancy and risk for preeclampsia, so it’s the <a href="https://www.ncbi.nlm.nih.gov/pubmed/12748491">duration of exposure</a> before conception that counts most.</p>
<p>Setting up a profile of immune tolerance that supports healthy pregnancy seems to be specific to the <a href="https://www.ncbi.nlm.nih.gov/pubmed/21529966">conceiving partner</a>. Women who change partners <a href="http://www.biomedsearch.com/nih/paternal-role-in-pre-eclampsia/22936817.html">return to a baseline state</a>, and must rebuild immune tolerance with the new partner.</p>
<p>Women who use <a href="https://www.ncbi.nlm.nih.gov/pubmed/2810672">barrier methods such as condoms or cervical caps</a> (which lower the exposure of the vagina and cervix to seminal fluid and sperm), and then conceive shortly after stopping contraception, have an <a href="https://www.ncbi.nlm.nih.gov/pubmed/12748491">elevated risk of preeclampsia</a>. </p>
<p>In contrast, women using an <a href="https://www.ncbi.nlm.nih.gov/pubmed/25854682">intrauterine device</a> before conception <a href="https://www.ncbi.nlm.nih.gov/pubmed/2810672">have been found</a> to have a slightly lower risk of preeclampsia.</p>
<h2>Sex during IVF can increase conception chances</h2>
<p>The importance of sex in creating the right environment for healthy pregnancy is also observed in clinical studies in IVF and other methods of assisted reproduction. Fertility is improved when couples have intercourse in the period when an embryo is transferred to the uterus. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/25281684">Combined data</a> from more than 2000 patients across seven studies showed the occurrence of a detectable pregnancy increased by 24% after vaginal contact with seminal fluid near the time of egg collection or embryo transfer. A <a href="https://www.ncbi.nlm.nih.gov/pubmed/11098040">study</a> of Australian and Spanish couples showed intercourse in the days just before or just after embryo transfer boosted pregnancy rates by 50%. </p>
<p>These studies focused on the early stages of pregnancy, with further research required to assess whether sexual intercourse influences rates of full term pregnancy after assisted reproduction. </p>
<p>Absence of exposure to seminal fluid may be one factor explaining why preeclampsia incidence is <a href="https://www.ncbi.nlm.nih.gov/pubmed/10469693">higher</a> after use of donated eggs or donor sperm, where prior female contact with the donor transplantation antigens has not occurred. The elevated risk after using donor semen <a href="https://www.ncbi.nlm.nih.gov/pubmed/19232411">can be reduced</a> if multiple prior insemination cycles take place with the same donor. </p>
<p>In couples who conceive using a modified version of IVF known as ICSI (intracytoplasmic sperm injection), preeclampsia incidence is also <a href="https://www.ncbi.nlm.nih.gov/pubmed/11879865">higher</a> in women who experience minimal exposure to their partner’s transplantation antigens due to very low sperm counts. </p>
<p>In some couples, an imbalance in seminal fluid composition or immune system factors may inhibit or slow down establishment of the <a href="https://www.ncbi.nlm.nih.gov/pubmed/27485480">tolerant immune profile in women</a>. In other couples, there may be immunological incompatibility that impairs tolerance, regardless of time spent together. </p>
<p>Maybe some couples may just <a href="https://www.ncbi.nlm.nih.gov/pubmed/22114108">need a little longer</a> having sex for pregnancy to occur. </p>
<h2>Immune system acts as a gatekeeper in pregnancy</h2>
<p>It is interesting to consider why the immune system is so closely involved in reproduction. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/20347158">One theory</a> is that females have evolved the ability to sense and respond to the signals in seminal fluid, in order to discern the quality or “fitness” of the male partner’s genetics. Scientists are now seeking to define the key signals on the male and female sides that promote tolerance. </p>
<p>Also, since male smoking, being overweight and other factors may shape <a href="https://www.ncbi.nlm.nih.gov/pubmed/27485480">how a woman responds to intercourse</a> in a biological sense, it helps explains why dad’s health is <a href="https://www.ncbi.nlm.nih.gov/pubmed/25124428">just as important</a> as that of the mother in preparing for pregnancy.</p><img src="https://counter.theconversation.com/content/67847/count.gif" alt="The Conversation" width="1" height="1" />
<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>Health benefits come with regular sexual contact with the same male partner before pregnancy commences.Sarah Robertson, Professor and Director, Robinson Research Institute, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.