Chapter 12. Sex: Evolutionary, Hormonal, and Neural Bases

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Amy Maxmen Male ducks respond to sexual competition by growing either an extra-long penis or a nub of flesh, a new study finds. The unusual phenomena occurred in two species studied: the lesser scaup (Aythya affinis) and the ruddy duck (Oxyura jamaicensis). It suggests that penis size — in line with many traits and behaviours meant to impress or allow impregnation of the opposite sex — involves a trade-off between the potential to reproduce and to survive. Patricia Brennan, an evolutionary biologist at Mount Holyoke College in South Hadley, Massachusetts, compared the penises of ducks kept in male–female pairs to those housed with multiple males per female. The findings are published in a study on 20 September in The Auk: Ornithological Advances1. “If they were alone with a female, the males just grew a normal-sized penis, but if there were other males around, they had the ability to change dramatically,” Brennan says. “So evolution must be acting on the ability to be plastic — the ability to invest only in what is needed in your current circumstance.” Because evolutionary success relies on reproduction, genitals are adapted to meet the varied circumstances that every animal faces. Some male ducks, for example, have penises in the shape of corkscrews to navigate the labyrinth-like vaginas of their female counterparts. An earlier study by Brennan found that females’ anatomy evolved to prevent access to undesirable males who force copulation2. To mate successfully with their chosen partners, Brennan says, female ducks assume a posture that allows males to enter them fully and deposit sperm near eggs. © 2017 Macmillan Publishers Limited,

Keyword: Sexual Behavior; Evolution
Link ID: 24086 - Posted: 09.21.2017

Cordelia Fine argues no; Joe Herbert says yes. Cordelia Fine: A common assumption, which I refer to as the ‘Testosterone Rex’ view, is that testosterone is a proximal tool of distal evolutionary processes, acting via the brain (prenatally, then from pubescence) to shape sex differences in behaviour that would have been differentially reproductively advantageous for men versus women in our ancestral past. Joe, as you put it in your book Testosterone: Sex, power and the will to win, ‘for [male] reproduction to be successful, testosterone has to act on many parts of the male to make him fit for the competitive world of male sexuality’. So, for example, males’ greater testosterone exposure predisposes them to be more risk-taking and competitive than females – an idea sometimes called on to help explain gender gaps in risky and competitive occupations, a category which happens to include most high-status and well-remunerated roles. So what exactly does testosterone do? Testosterone acts directly on the brain, but the circulating level of testosterone in the blood is just one part of a highly complex, multi-faceted system. What’s more, different species appear to tweak those system dials in different ways, enabling cross-species differences in relations between hormones and behaviour. What do we need to try to explain when it comes to humans? One important feature of sex differences in behaviour is that these are much smaller than sex differences in testosterone exposure (a lot of overlap between female and male populations, and very little, respectively). This casts serious doubt on the assumption that more testosterone means more masculinity, and that men must inevitably be more masculine because they have higher absolute levels of testosterone on average. © Copyright 2000-2017 The British Psychological Society

Keyword: Sexual Behavior
Link ID: 24085 - Posted: 09.20.2017

By Jessica Hamzelou Aggression and sexual behaviour are controlled by the same brain cells in male mice – but not in females. The finding suggests that males are more likely to become aggressive when they see a potential mate than females. The brain regions that contain these cells look similar in mice and humans, say the researchers behind the study, but they don’t yet know if their finding has relevance to human behaviour. Similar to humans, male mice are, on the whole, more aggressive than females. Because of this, most research into aggression has overlooked females, says Dayu Lin at New York University. “I would say 90 per cent of aggression studies have been done in males,” she says. “We know very little about aggression in females.” But females can be aggressive too. For instance, female mice can be aggressive when protecting their newborn pups. In 2011, Lin and her colleagues studied a region of the brain called the hypothalamus, responsible for regulating many different behaviours. They discovered a set of cells within this region in male mice that controlled both aggressive and sexual behaviours. When the cells were shut off, the mice didn’t mate or show aggression, but both behaviours could be triggered when the cells were stimulated. © Copyright New Scientist Ltd.

Keyword: Aggression; Sexual Behavior
Link ID: 24076 - Posted: 09.19.2017

Grant Tomkinson and Makailah Dyer Examine your fingers. Which is longer? Is it the index finger (the finger you use to point with — technically the second digit, or 2D, counting the thumb), or the ring finger (the fourth digit, or 4D)? The relative length of the index and ring fingers is known as the digit ratio or the 2D:4D. For example, if your index finger is 2.9 inches (or 7.4 cm) long, and your ring finger is 3.1 inches (or 7.9 cm) long, your digit ratio is 0.935 (i.e., 2.9/3.1 or 7.4/7.9). Males typically have lower digit ratios (the ring finger in males is typically longer than the index finger) than females (the fingers are about the same length in females). The ratio does not change much with age. There is some indirect evidence that the digit ratio is determined during early fetal development — as early as the second trimester of pregnancy — by the balance between the steroid hormones testosterone and estrogen. The developing ring finger has a high number of receptors for testosterone: the more testosterone the fetus produces, the longer the ring finger, and so the lower the digit ratio. Our research team wanted to take this finger research a step further: could the differences predict athletic ability, and, if so, how?

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 24062 - Posted: 09.14.2017

Reza Ziai In recent years, many individuals on the political left have been earnestly conveying the message that what a person is attracted to (i.e. mate preference) is entirely constructed by the environment. Their reasons for doing so seem sincere. Take for example, the oft-cited connection between the media’s portrayal of female standards of beauty and eating disorders like anorexia and bulimia. To postmodernists, since standards of attraction are seen as being environmentally produced, the media’s “stereotypical” portrayal of female beauty is also seen as being environmentally produced, sexist, and therefore, unjustifiable. Postmodernism (see also Critical Theory and The Frankfurt School) combats this perceived bigotry by attempting to justify the need to enforce changes in the status quo. Most notably in recent news, many liberal arts students have attempted to deplatform speakers like Charles Murray, Christina Hoff Sommers, and Ayaan Hirsi Ali from speaking on their campuses. Limiting free speech has been just one way that postmodernism and people on the far-left have tried to control the environment. Reforms (sometimes mandatory ones) have been seen in pronoun usage, soft drink sizes, the media, children’s toys, social attitudes, etc. Their idea is that since the environment (and not biology) affects our attitude, if you change the environment, you change the person, and thus, society is improved. By minimizing or ignoring the role that biology has on human nature, postmodernists can effectively blame all of the ills of the modern world on poorly designed laws, U.S. foreign policy, or Western cultural attitudes. Those who dissent from their view can be denounced as bigots and cast aside.

Keyword: Sexual Behavior
Link ID: 24061 - Posted: 09.14.2017

Devin Coldewey We count on machine learning systems for everything from creating playlists to driving cars, but like any tool, they can be bent towards dangerous and unethical purposes as well. Today's illustration of this fact is a new paper from Stanford researchers, who have created a machine learning system that they claim can tell from a few pictures whether a person is gay or straight. The research is as surprising as it is disconcerting. In addition to exposing an already vulnerable population to a new form of systematized abuse, it strikes directly at the egalitarian notion that we can't (and shouldn't) judge a person by their appearance, nor guess at something as private as sexual orientation from something as simple as a snapshot or two. But the accuracy of the system reported in the paper seems to leave no room for mistake: this is not only possible, it has been achieved. It relies on cues apparently more subtle than most can perceive — cues many would suggest do not exist. And it demonstrates, as it is intended to, a class of threat to privacy that is entirely unique to the imminent era of ubiquitous computer vision. Before discussing the system itself, it should be made clear that this research was by all indications done with good intentions. In an extensive set of authors' notes that anyone commenting on the topic ought to read, Michal Kosinski and Yilun Wang address a variety of objections and questions. Most relevant are perhaps their remarks as to why the paper was released at all: We were really disturbed by these results and spent much time considering whether they should be made public at all. We did not want to enable the very risks that we are warning against. The ability to control when and to whom to reveal one’s sexual orientation is crucial not only for one’s well-being, but also for one’s safety.

Keyword: Sexual Behavior
Link ID: 24046 - Posted: 09.08.2017

By NATALIE ANGIER A normal human baby, according to psychologists, will cry about two hours over the course of a day. A notorious human crybaby, according to her older siblings, parents and the building superintendent, will cry for two hours every two hours, refusing to acknowledge any distinction between crying and other basic infant activities, like “being awake” or “breathing.” Current and former whine enthusiasts, take heart. It turns out that infant crying is not only as natural and justifiable as breathing: The two acts are physically, neurologically, primally intertwined. Scientists have discovered that the small cluster of brain cells in charge of fast, active respiration also grant a baby animal the power to cry. Reporting in the Proceedings of the National Academy of Sciences, Carmen Birchmeier and Luis Hernandez-Miranda, of the Max Delbruck Center for Molecular Medicine in Berlin, and their colleagues showed that infant mice stripped of this key node — a mere 17,000 neurons, located in the evolutionarily ancient hindbrain — can breathe slowly and passively, but not vigorously or animatedly. When they open their mouths to cry, nothing comes out. As a result, their mothers ignore them, and the poorly breathing pups quickly die. “This was an astonishing finding,” Dr. Birchmeier said. “The mother could see the pups and smell the pups, but if they didn’t vocalize, it was as though they didn’t exist.” The new study is just one in a series of recent reports that reveal the centrality of crying to infant survival, and how a baby’s bawl punches through a cluttered acoustic landscape to demand immediate adult attention. The sound of an infant’s cry arouses a far quicker and stronger response in action-oriented parts of the adult brain than do similarly loud or emotionally laden noises, like a dog barking or a neighbor weeping. © 2017 The New York Times Company

Keyword: Sexual Behavior; Animal Communication
Link ID: 24037 - Posted: 09.05.2017

By Aylin Woodward If you’re trying to overthrow the boss, you might need a friend to back you up. The same is true for female macaques, who need allies to resist authority and take down more powerful members of the group. Most primates have social hierarchies in which some individuals are dominant over the others. For rhesus macaques, these strict hierarchies are organised around female relationships. Lower-ranked females have little social mobility and must silently bare their teeth to higher-ranked females. The signal means “I want you to know that I know that you out-rank me” and is important in communicating social rank, says Darcy Hannibal at the University of California, Davis. “They are ‘bending the knee’.” But Hannibal and her colleagues have discovered that subordinate females can override the status quo. To do this, female macaques form alliances with family, friends or both. These alliances help females maintain or increase their social rank and compete for resources. A female who wants to challenge those higher up needs this help, says Hannibal. Insubordination events were more likely if the lower-ranked female was older. They were most likely if the subordinate outweighed the dominant female by 7 kilograms and the dominant female had no family allies. The more allies the subordinate female had, and the more days her mother was present in the group, the more often she would exhibit insubordinate behaviour. © Copyright New Scientist Ltd.

Keyword: Aggression; Sexual Behavior
Link ID: 24005 - Posted: 08.28.2017

Darby Saxbe Postpartum depression has become more visible as celebrity moms including Brooke Shields, Drew Barrymore and Chrissy Teigen have publicly shared their struggles with feeling sad and hopeless after birth. But when a father – Adam Busby, from reality TV show “OutDaughtered” – recently opened up about his own postpartum depression, he received instant backlash, including comments telling him to “man up.” Despite the skepticism, postpartum depression in fathers is very real, with estimates that around 10 percent of men report symptoms of depression following the birth of a child, about double the typical rate of depression in males. Postpartum depression in women has been linked with hormonal shifts, but the role of hormones in men’s postpartum depression has been unknown. In an attempt to solve this mystery, my colleagues and I recently tested whether men’s levels of the hormone testosterone are related to their postpartum depression risk during early parenthood. We found that men’s testosterone levels might predict not only their own postpartum depression risk, but their partner’s depression risk as well. Testosterone is an androgen hormone, responsible for the development and maintenance of male secondary sex characteristics. It promotes muscle mass and body hair growth, and motivates sexual arousal and competitive behavior. Many studies have found that testosterone dips in new fathers across the animal kingdom. Among animals that engage in the biparental care of offspring – Mongolian gerbils, Djungarian hamsters, California mice and cotton-top tamarins – males show lower testosterone levels following the birth of pups. © 2010–2017, The Conversation US, Inc.

Keyword: Depression; Hormones & Behavior
Link ID: 24001 - Posted: 08.26.2017

By Elizabeth Pennisi GRONINGEN, THE NETHERLANDS—For insects such as the tobacco budworm moth, beauty is actually in the “nose” of the beholder, as females use chemical scents called pheromones to lure in potential mates. And—as in people—some moths are attractive. Others … well, not so much. Now, evolutionary biologists have learned that these unattractive female moths better their odds of mating by hanging out with their more attractive counterparts. “We often think of mate choice as a perfect and entirely binary process—you are attractive or you are not—but this is clearly not the case,” says Therésa Jones, a behavioral and evolutionary ecologist at the University of Melbourne in Australia, who was not involved with the work. Wouter Halfwerk, a behavioral ecologist at the University of Amsterdam, adds that the results, reported this week here at the XIV Congress of the European Society of Evolutionary Biology, “provide an answer of how unattractiveness can evolve, which challenges our notion of beauty.” The new work was done by Astrid Groot, an evolutionary biologist at the University of Amsterdam who studies the evolution of sexual signals. She specializes in the tobacco budworm moth (Heliothis virescens) because so much is already known about its caterpillar, a widespread crop pest in the United States often caught by farmers with pheromone-scented traps. In field studies, she and other researchers noticed that some females never seem to attract males. But how could they reproduce enough to pass along their less-than-sexy scent? To find out, she and colleagues raised multiple generations of the budworm in the lab, testing each generation’s females for how quickly males home in on their scents. By separately breeding the most and least attractive females, the researchers gradually created two strains, one of supersexy smellers and one of, for lack of a better word, stinkers. © 2017 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 24000 - Posted: 08.26.2017

By Sam Wong It seems you can judge an athlete by their face – if they are a man, that is. Male athletes with a higher world ranking tend to be judged as more attractive by women, but there is no such trend among women. Several studies have previously reported a link between facial attractiveness and sporting performance in men, leading to suggestions that women respond to facial cues that reflect athletic ability in potential partners. Some have suggested this is because, in our evolutionary past, women might have benefited from choosing a partner with speed, skill and endurance. As a better hunter, the idea goes, he would have brought home more food, and he might pass on his fitness to their children. But these studies have been criticised, notably for only looking at men. They also tended to focus on team sports, therefore failing to isolate individual performance. To find more evidence, Tim Fawcett and colleagues at the University of Exeter, UK, collected photos of 156 men and women who competed at the 2014 Winter Olympics in the biathlon – an event combining cross-country skiing and shooting. Each athlete was rated for their facial attractiveness by members of the opposite sex, who didn’t know the purpose of the study. © Copyright New Scientist Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 23992 - Posted: 08.25.2017

Tina Hesman Saey Add a new ingredient to the sugar, spice and everything nice needed to make girls. A protein called COUP-TFII is necessary to eliminate male reproductive tissue from female mouse embryos, researchers report in the Aug. 18 Science. For decades, females have been considered the “default” sex in mammals. The new research overturns that idea, showing that making female reproductive organs is an active process that involves dismantling a primitive male tissue called the Wolffian duct. In males, the Wolffian duct develops into the parts needed to ejaculate sperm, including the epididymis, vas deferens and seminal vesicles. In females, a similar embryonic tissue called the Müllerian duct develops into the fallopian tubes, uterus and vagina. Both duct tissues are present in early embryos. A study by French endocrinologist Alfred Jost 70 years ago indicated that the testes make testosterone and an anti-Müllerian hormone to maintain the Wolffian duct and suppress female tissue development. If those hormones are missing, the Wolffian duct degrades and an embryo by default develops as female, Jost proposed. That’s the story written in textbooks, says Amanda Swain, a developmental biologist at the Institute of Cancer Research in London. But the new study “demonstrates that females also have a pathway to make sure you don’t get the wrong ducts,” says Swain, who wrote a commentary in the same issue of Science. |© Society for Science & the Public 2000 - 2017.

Keyword: Sexual Behavior
Link ID: 23976 - Posted: 08.19.2017

By Jenna Gallegos Pathogens are real jerks. As if infecting and killing plants and animals isn’t bad enough, they can also turn their hosts into zombies that spread the pathogens to their next victim. Now scientists report that bacteria make some victims summon other victims as their dying act. The bacteria hijack the chemical signaling pathway of insects, making them release a burst of hormones that serve as a beacon to attract friends and potential mates right before the bacteria kill off the host. Like malware marauding as an enticing link, the bacteria attract and then infect. Fruit flies are generally pretty good at avoiding hazards. They can detect when food is infected with a dangerous mold or when a parasitic wasp is nearby, said Markus Knaden, a researcher at the Max Planck Institute for Chemical Ecology in Jena, Germany, who was involved in the study. In both cases, the flies won’t lay their eggs near the infectious agent. That’s why Knaden and colleagues at Cornell University were so surprised when they found that flies were actually attracted to other insects with a certain bacterial infection. “If you’re sitting in a theater and someone next to you is coughing, you move to another chair,” said Bill Hansson, one of the Max Planck authors of the study, published Wednesday in the journal Nature Communications. They expected flies to behave the same way, but instead, healthy flies found their sick friends to be extremely attractive. © 1996-2017 The Washington Post

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 23964 - Posted: 08.16.2017

Alice H. Eagly It’s no secret that Silicon Valley employs many more men than women in tech jobs. What’s much harder to agree on is why. The recent anti-diversity memo by a now former Google engineer has pushed this topic into the spotlight. The writer argued there are ways to explain the gender gap in tech that don’t rely on bias and discrimination – specifically, biological sex differences. Setting aside how this assertion would affect questions about how to move toward greater equity in tech fields, how well does his wrap-up represent what researchers know about the science of sex and gender? As a social scientist who’s been conducting psychological research about sex and gender for almost 50 years, I agree that biological differences between the sexes likely are part of the reason we see fewer women than men in the ranks of Silicon Valley’s tech workers. But the road between biology and employment is long and bumpy, and any causal connection does not rule out the relevance of nonbiological causes. Here’s what the research actually says. There is no direct causal evidence that biology causes the lack of women in tech jobs. But many, if not most, psychologists do give credence to the general idea that prenatal and early postnatal exposure to hormones such as testosterone and other androgens affect human psychology. In humans, testosterone is ordinarily elevated in males from about weeks eight to 24 of gestation and also during early postnatal development. © 2010–2017, The Conversation US, Inc.

Keyword: Sexual Behavior; Development of the Brain
Link ID: 23963 - Posted: 08.16.2017

Allison Aubrey What we eat can influence more than our waistlines. It turns out, our diets also help determine what we smell like. A recent study found that women preferred the body odor of men who ate a lot of fruits and vegetables, whereas men who ate a lot of refined carbohydrates (think bread, pasta) gave off a smell that was less appealing. Skeptical? At first, I was, too. I thought this line of inquiry must have been dreamed up by the produce industry. (Makes a good marketing campaign, right?) But it's legit. "We've known for a while that odor is an important component of attractiveness, especially for women," says Ian Stephen of Macquarie University in Australia. He studies evolution, genetics and psychology and is an author of the study. From an evolutionary perspective, scientists say our sweat can help signal our health status and could possibly play a role in helping to attract a mate. How did scientists evaluate the link between diet and the attractiveness of body odor? They began by recruiting a bunch of healthy, young men. They assessed the men's skin using an instrument called a spectrophotometer. When people eat a lot of colorful veggies, their skin takes on the hue of carotenoids, the plant pigments that are responsible for bright red, yellow and orange foods. "The carotenoids get deposited in our skin," explains Stephen. © 2017 npr

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 23961 - Posted: 08.15.2017

Conor Friedersdorf This week, headlines across a diverse array of media outlets proclaimed that at least one Google employee was so antagonistic to women that he circulated a 10-page “anti-diversity screed.” That is how Gizmodo characterized the now infamous internal memo when publishing it Saturday. Similar language was used in headlines at Fox News, CNN, ABC News, the BBC, NBC News, Time, Slate, Engadget, The Huffington Post, PBS, Fast Company, and beyond (including a fleeting appearance in a headline here at The Atlantic). But love or hate the memo, which makes a number of substantive claims, some of which I regard as wrongheaded (and which would’ve benefitted greatly from an editor with more emotional intelligence than the author to help him avoid alienating his audience, even if he was determined to raise all of the same arguments), the many characterizations of the memo as “anti-diversity” are inaccurate. Using that shorthand is highly misleading. As many who read past the headlines would later observe, its author, who was later fired, began, “I value diversity and inclusion, am not denying that sexism exists, and don’t endorse using stereotypes. When addressing the gap in representation in the population, we need to look at population level differences in distributions. If we can’t have an honest discussion about this, then we can never truly solve the problem.” The balance of his memo argues that he is not against pursuing greater gender diversity at Google; he says it is against the current means Google is using to pursue that end and the way the company conceives of tradeoffs between the good of diversity and other goods. (c) 2017 by The Atlantic Monthly Group.

Keyword: Sexual Behavior
Link ID: 23941 - Posted: 08.10.2017

By NICHOLAS BAKALAR The incidence of stroke has declined in recent years, but only in men. Researchers studied stroke incidence in four periods from 1993 to 2010 in five counties in Ohio and Kentucky. There were 7,710 strokes all together, 57.2 percent of them in women. After adjusting for age and race, they found that stroke incidence in men had decreased to 192 per hundred thousand men in 2010, down from 263 in 1993–94. But for women the incidence was 198 per hundred thousand in 2010, down from 217 in 1993–94, a statistically insignificant change. The study is in Neurology. Most of the difference was in ischemic stroke, the most common cause, resulting from a blocked blood vessel supplying blood to the brain. No one knows why there has been no improvement in women, but the lead author, Dr. Tracy E. Madsen, an assistant professor of emergency medicine at Brown, said that some risk factors have a stronger effect in women than in men. Risk factors for stroke include high blood pressure, heart disease, diabetes and smoking. “Maybe we’re not controlling risk factors to the same extent in women. Or maybe there’s a biological difference in the way these risk factors cause strokes in men versus women.” In any case, Dr. Madsen said, “It’s important for women to know they are at risk. Stroke has been considered a male disease, but we know that it is very prevalent in women and has a high risk of disability and death.” © 2017 The New York Times Company

Keyword: Stroke; Sexual Behavior
Link ID: 23939 - Posted: 08.10.2017

By Jamie Strashin, The look on Melissa Bishop's face said it all. The Canadian 800-metre star had just run the race of her life, at the best possible moment, on the world's biggest stage. "I have never run faster in my life. It's the smartest race I have ever put down on a track," Bishop said of her performance in the final at the Rio Olympics last summer. But it still wasn't enough. Despite setting a new Canadian record (which she has since broken by running a 1:57.01), Bishop finished fourth in the Rio final, missing a bronze medal by 13 hundredths of a second. Perhaps more distressingly, she crossed the line close to two seconds slower than gold medallist Caster Semenya. "I remember seeing my agent and just falling into his arms, thinking, I can't believe this just happened. What just happened?" Bishop recalled. "And then I saw my dad, and my dad is a very emotional man and he was livid. Not because of how I raced, but because of the scenario we were in. And he just kept telling me, 'You have nothing to be ashamed of.'" The "scenario" of finishing well behind Semenya is a familiar one for competitors since the South African burst onto the scene at the 2009 world track and field championships. As an 18-year-old in Berlin, Semenya blasted away her competition, winning by almost two and a half seconds and clocking the fastest time of the year. Caster Semenya dominates 800m at 2009 world championships ©2017 CBC/Radio-Canada.

Keyword: Sexual Behavior
Link ID: 23933 - Posted: 08.09.2017

/ By Florence Williams The 17th century ushered in an astonishing age of scientific discovery, from Galileo’s positioning of the sun in the heavens to Newton’s Laws of Motion to Francis Bacon’s empiricism. Armed with new swagger and understanding, the scientific rationalists of the day figured the pivot from astronomy and physics to biology would be a piece of cake. The workings of the universe had been proved to adhere to laws and formulas. All would be properly unveiled in due time. “The bold men of science,” Edward Dolnick writes, “raced off to take on the mystery of life and promptly face-planted.” How mistaken they were. As Edward Dolnick writes in his amusing and informative “The Seeds of Life,” “The bold men of science raced off to take on the mystery of life and promptly face-planted.” In fact, they were fairly undone, partly by their own pigheaded biases and partly by the truly mystifying matters of genes and heredity, for which they were woefully ill prepared. It was not until 1875 that a German scientist finally put the sperm and the egg together conceptually. The journey to that insight was sometimes comical, sometimes misguided, and usually revealing of cultural mores, gender politics, and societal blind spots. Consider, for example, the common scientific belief that a woman’s contribution to baby-making must surely be minimal. Copyright 2017 Undark

Keyword: Sexual Behavior; Development of the Brain
Link ID: 23921 - Posted: 08.07.2017

Daniel Trotta NEW YORK (Reuters) - While President Donald Trump has thrust transgender people back into the conflict between conservative and liberal values in the United States, geneticists are quietly working on a major research effort to unlock the secrets of gender identity. A consortium of five research institutions in Europe and the United States, including Vanderbilt University Medical Center, George Washington University and Boston Children's Hospital, is looking to the genome, a person's complete set of DNA, for clues about whether transgender people are born that way. Two decades of brain research have provided hints of a biological origin to being transgender, but no irrefutable conclusions. Now scientists in the consortium have embarked on what they call the largest-ever study of its kind, searching for a genetic component to explain why people assigned one gender at birth so persistently identify as the other, often from very early childhood. (reut.rs/2w3Ozg9) Researchers have extracted DNA from the blood samples of 10,000 people, 3,000 of them transgender and the rest non-transgender, or cisgender. The project is awaiting grant funding to begin the next phase: testing about 3 million markers, or variations, across the genome for all of the samples.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 23919 - Posted: 08.05.2017