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

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By Meredith Wadman BethAnn McLaughlin has no time for James Watson, especially not when the 90-year-old geneticist is peering out from a photo on the wall of her guest room at Cold Spring Harbor Laboratory’s Banbury Center. “I don’t need him staring at me when I’m trying to go to sleep,” McLaughlin told a December 2018 gathering at the storied New York meeting center as she projected a photo of her redecorating job: She had hung a washcloth over the image of Watson, who co-discovered DNA’s structure, directed the lab for decades—and is well-known for racist and sexist statements. The washcloth image was part of McLaughlin’s unconventional presentation—by turns sobering, hilarious, passionate, and profane—to two dozen experts who had gathered to wrestle with how to end gender discrimination in the biosciences. McLaughlin, a 51-year-old neuroscientist at Vanderbilt University Medical Center (VUMC) in Nashville, displayed the names of current members of the National Academy of Sciences (NAS) who have been sanctioned for sexual harassment. She urged other NAS members—several of whom sat in the room—to resign in protest, “as one does.” She chided institutions for passing along “harassholes” to other universities. “The only other places that do this are the Catholic Church and the military,” she said. In the past 9 months, McLaughlin has exploded into view as the public face of the #MeToo movement in science, wielding her irreverent, sometimes wickedly funny Twitter presence, @McLNeuro, as part cudgel, part cheerleader’s megaphone. In June 2018, she created a website,, where scores of women in science, technology, engineering, and math (STEM) have posted mostly anonymous, often harrowing tales of their own harassment. In just 2 days that month, she convinced the widely used website to remove its “red hot chili pepper” rating for “hotness.” And after launching an online petition, she succeeded last fall in spurring AAAS, which publishes Science, to adopt a policy allowing proven sexual harassers to be stripped of AAAS honors. © 2018 American Association for the Advancement of Science

Keyword: Sexual Behavior; Aggression
Link ID: 25961 - Posted: 02.13.2019

By Pam Belluck For the first time, a national health panel has recommended a way to prevent depression during and after pregnancy. This condition, known as perinatal depression, affects up to one in seven women and is considered the most common complication of pregnancy. The panel, the United States Preventive Services Task Force, said two types of counseling can help keep symptoms at bay. Its recommendation means that under the Affordable Care Act, such counseling must be covered by insurance with no co-payment. Here’s a guide to what to look for and how to get help. What is perinatal depression and what are the signs that you or a loved one might be experiencing it? Perinatal depression can occur during pregnancy or any time within a year after childbirth. As defined by the panel, it can involve major or minor depressive symptoms that last for at least two weeks, including loss of energy or concentration, changes in sleeping and eating patterns, feelings of worthlessness or suicidal thoughts. It’s not the same as the “baby blues,” which is less severe and doesn’t last as long. The panel said “baby blues” can occur right after childbirth and can include crying, irritability, fatigue and anxiety, symptoms that usually disappear within 10 days. Many things can raise a woman’s risk of depression during and after pregnancy. Having a personal or family history of depression is a significant risk factor. Others include a range of experiences that can generate stress: recent divorce or relationship strain; being a victim of abuse or domestic violence; being a single mother or a teenager; having an unplanned or unwanted pregnancy. Economic burdens increase the risk — about one in three low-income women develops depression during or after pregnancy. © 2019 The New York Times Company

Keyword: Depression; Sexual Behavior
Link ID: 25959 - Posted: 02.13.2019

By Natalie Angier Most female flies take a low-rent approach to parenthood, depositing scores of seed-sized eggs in the trash or on pet scat to hatch, leaving the larvae to fend for themselves. Not so the female tsetse fly. She gestates her young internally, one at a time, and gives birth to them live. When each extravagantly pampered offspring pulls free of her uterus after nine days, fly mother and child are pretty much the same size. “It’s the equivalent of giving birth to an 18-year-old,” said Geoffrey Attardo, an entomologist who studies tsetse flies at the University of California, Davis. The newborn tsetse fly looks like a hand grenade and moves like a Slinky, and if you squeeze it too hard the source of its plumpness becomes clear — or rather a telltale white. The larva, it seems, is just a big bag of milk. “Rupture the gut,” Dr. Attardo said, “and the milk comes spilling out.” And milk it truly is — a nutritional, biochemical and immunological designer fluid that the mother fly’s body has spun from her blood meals and pumped into her uterus, where her developing young greedily gulped it down. Thus fattened on maternal largess, a tsetse fly larva can safely burrow underground and pupate for 30 days before emerging as a full-blown adult with a nasty bite and a notorious capacity to transmit a deadly disease called sleeping sickness. In a recent chemical and genetic analysis of tsetse fly milk, Dr. Attardo and his colleagues were startled to discover how similar it was to the product of the beloved gland that stamps us as mammals. “I was expecting something completely off the wall and different,” he said. “But there are frightening, fascinating overlaps with mammalian milk in the kinds of proteins we see.” © 2019 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 25955 - Posted: 02.12.2019

By Lisa Rapaport New mothers who have friends ready to step in and help them, tend to have toddlers who score better on cognitive tests than the babies of women with smaller social support networks, a U.S. study suggests. Strong social ties to friends and family have long been linked to better behavioral and physical health outcomes for adults. And plenty of previous research also indicates that infants’ and toddlers’ bonds with caregivers can have a lasting impact on children’s emotional, intellectual and social development. But less is known about how the caregivers’ own social connections might influence early childhood cognitive development. For the current study, researchers examined data on 1,082 mother-child pairs. They questioned women about their family structure, friendships and relationships in their communities and also looked at test results from cognitive assessments done when children were 2 years old. Overall, mothers had an average of 3.5 friends in their social support networks. The kids of mothers with more than that tended to have higher cognitive test scores than the kids of those who had fewer, suggesting “network conditions were significantly associated with early cognitive development in children,” the study authors wrote. © 1996-2019 The Washington Post

Keyword: Sexual Behavior; Development of the Brain
Link ID: 25954 - Posted: 02.12.2019

By James Gorman If you want to know what makes hummingbirds tick, it’s best to avoid most poetry about them. Bird-beam of the summer day, — Whither on your sunny way? Whither? Probably off to have a bloodcurdling fight, that’s whither. John Vance Cheney wrote that verse, but let’s not point fingers. He has plenty of poetic company, all seduced by the color, beauty and teeny tininess of the hummingbird but failed to notice the ferocity burning in its rapidly beating heart. The Aztecs weren’t fooled. Their god of war, Huitzilopochtli, was a hummingbird. The Aztecs loved war, and they loved the beauty of the birds as well. It seems they didn’t find any contradiction in the marriage of beauty and bloodthirsty aggression. Scientists understood that aggression was a deep and pervasive part of hummingbird life. But they, too, have had their blind spots. The seemingly perfect match of nectar-bearing flowers to slender nectar-sipping beaks clearly showed that hummingbirds were shaped by co-evolution. It seemed clear that, evolutionarily, plants were in charge. Their need for reliable pollinators produced flowers with a shape that demanded a long slender bill. Hummingbird evolution obliged. But hummingbirds also heard the call of battle, which demanded a different evolutionary course. Some of those slender, delicate beaks have been reshaped into strong, sharp and dangerous weapons. In a recent paper organizing and summing up 10 years of research, Alejandro Rico-Guevara and his colleagues at the University of California, Berkeley, shared evidence gathered by high-speed video about how the deadly beaks are deployed in male-to-male conflict. Like the horns of bighorn sheep or the giant mandibles of stag beetles, hummingbird beaks are used to fight off rivals for mates. This is sexual selection, a narrow part of natural selection, in which the improvement of mating chances is the dominant force. © 2019 The New York Times Company

Keyword: Aggression; Evolution
Link ID: 25937 - Posted: 02.06.2019

Jon Hamilton Women tend to have more youthful brains than their male counterparts — at least when it comes to metabolism. While age reduces the metabolism of all brains, women retain a higher rate throughout the lifespan, researchers reported Monday in the journal Proceedings of the National Academy of Sciences. "Females had a younger brain age relative to males," says Dr. Manu Goyal, an assistant professor of radiology and neurology at Washington University School of Medicine in St. Louis. And that may mean women are better equipped to learn and be creative in later life, he says. The finding is "great news for many women," says Roberta Diaz Brinton, who wasn't connected with the study and directs the Center for Innovation in Brain Science at the University of Arizona Health Sciences. But she cautions that even though women's brain metabolism is higher overall, some women's brains experience a dramatic metabolic decline around menopause, leaving them vulnerable to Alzheimer's. The study came after Goyal and a team of researchers studied the brain scans of 205 people whose ages ranged from 20 to 82. Positron emission tomography scans of these people assessed metabolism by measuring how much oxygen and glucose was being used at many different locations in the brain. The team initially hoped to use the metabolic information to predict a person's age. So they had a computer study how metabolism changed in both men and women. © 2019 npr

Keyword: Sexual Behavior; Brain imaging
Link ID: 25933 - Posted: 02.05.2019

By Jordana Cepelewicz Genitals are among the fastest-evolving features in the animal kingdom. They’re also among the most diverse, arrayed in all shapes and sizes, adorned with spines, hooks and even teeth. Ducks have corkscrew-shaped genitalia. The male sea horse has a brood pouch that receives his mate’s eggs for fertilization and in which he nurtures the resulting offspring until birth. Female cabbage white butterflies have a hinged jaw inside their genital tract. Nature is full of strange reproductive organs with unusual uses. For the most part, though, certain genital morphologies are associated with males, others with females. But in 2014, a tiny insect called the barklouse broke even that rule when researchers reported that the females of all four species of a genus found in the caves of Brazil had a penis. It didn’t just look like a penis but acted like one, too: a penetrative organ the female insects used to anchor themselves to their mates during copulation. Moreover, complementary changes in the genitalia of the males had left them with a small pumping mechanism inside a membranous “vagina-like” cavity. Content from The Coca-Cola Company Sustainability and closed-loop recycling systems must now become a global priority, from emerging nations to the world's largest economies. Read More The finding not only piqued widespread interest (and amusement — the team was awarded a comedic Ig Nobel Prize in 2017), but also led to a debate about whether the scientists involved were correct to refer to the structure, called a gynosome, as a “female penis.” (Some experts, for instance, disagree with that characterization because the gynosome collects sperm rather than delivering it.) © 1996-2019 The Washington Post

Keyword: Sexual Behavior; Evolution
Link ID: 25928 - Posted: 02.04.2019

By Virginia Morell It’s hard to imagine a teen asking their mother for approval on anything. But a new study shows that male zebra finches—colorful songbirds with complex songs—learn their father’s tune better when mom “fluffs up” to signal her approval. This is the first time the songbirds, thought to be mere memorization machines, have been shown to use social cues for learning—putting them in an elite club that includes cowbirds, marmosets, and humans. The finding suggests other songbirds might also learn their tunes this way, and that zebra finches are better models for studying language development than thought. “Female zebra finches play an important role in male learning, in some ways even rivaling that of the male tutors,” says Karl Berg, an avian ecologist at the University of Texas in Brownsville, who was not involved in the new study. Previously, scientists knew only that the nonsinging females played some role in song acquisition, because males raised with deaf females develop incorrect songs. Researchers have long known that female brown-headed cowbirds make quick, lateral wing strokes to approve the songs of juvenile males (as in finches, only male cowbirds learn to sing). Most scientists discounted the cowbirds’ social cues as an isolated oddity, because the birds are brood parasites. But cowbirds’ similarities to zebra finches—both are highly social and use their songs to attract mates rather than claim territories—led Cornell University developmental psychobiologists Samantha Carouso-Peck and Michael Goldstein to wonder whether female finches also use social cues to help young males learn the best, mate-attracting songs. © 2018 American Association for the Advancement of Science.

Keyword: Animal Communication; Sexual Behavior
Link ID: 25922 - Posted: 02.01.2019

Susan Milius After some 20 years of theorizing, a scientist is publicly renouncing the “beautiful hypothesis” that male birds’ sexy songs could indicate the quality of their brains. Behavioral ecologist Steve Nowicki of Duke University called birdsong “unreliable” as a clue for choosy females seeking a smart mate, in a paper published in the March 2018 Animal Behaviour. He will also soon publish another critique based on male songbirds that failed to score consistently on learning tests. And in what he calls a “public service announcement,” Nowicki summarized the negative results of those tests on January 4 at the annual meeting of the Society for Integrative and Comparative Biology in Tampa, Fla. “This was a beautiful hypothesis that got beaten up by data,” he says. Knowing that something about male singing matters to a female songbird, Nowicki and other researchers once proposed that the quality of singing might indicate a bird’s brainpower. The idea was that, because songbirds need to learn their songs, females could select males with the best brain development by selecting those singing the most precisely copied songs. A brainier male might be better at hunting baby food or spotting predators, thus helping more chicks to survive. Or braininess might signal an indirect benefit, such as contributing good genes to chicks. The first evidence for the notion that birdsong indicates bird smarts came from Neeltje Boogert at the University of Exeter in England, whose research suggested female zebra finches preferred smarter males with more complex songs. But subsequent studies have found evidence both supporting and contradicting the theory. To try to settle the matter, Nowicki and collaborators hand-raised 19 male song sparrows in the lab, controlling which songs the little birds heard as examples to copy so that it was clear how well each youngster learned each song. |© Society for Science & the Public 2000 - 2019

Keyword: Animal Communication; Sexual Behavior
Link ID: 25900 - Posted: 01.26.2019

Emily Chung · CBC News · Could the pain you feel in your body be all in your head? At least some of it might be — if you're a man (or a male mouse), a new study has found. Male humans and male mice — but not females of either species — both became hypersensitive to pain when put in an environment where they had previous had a painful experience, reports a new Canadian-led study published last week in the journal Current Biology. "The sex difference was completely unexpected," said Loren Martin, the University of Toronto Mississauga assistant professor of psychology who led the study. While there was no reason to believe males and females would respond differently, if they did, he would have expected females, not males, to develop pain hypersensitivity, since they're generally more sensitive to pain and more prone to chronic pain. Martin originally ran an experiment on mice while he was a postdoctoral researcher in the lab of McGill University professor Jeffrey Mogil, who holds two research chairs related to pain. They wanted to to see how the mice would react if brought back to a place where they had had a painful experience — a 30-minute tummy ache cause by dilute vinegar in their stomachs — and whether they could be conditioned to be hypersensitive to pain. The reason they were interested is because there is growing evidence that chronic pain is linked to biochemical "rewiring" in nerves similar to what happens with the formation of memories in the brain, and may itself be akin to or linked to memory, Martin said. If that's the case, chronic pain could potentially be treated by de-rewiring the nerves back to their normal state. ©2018 CBC/Radio-Canada

Keyword: Pain & Touch; Sexual Behavior
Link ID: 25864 - Posted: 01.15.2019

By Karen Weintraub Sometimes a whale just wants to change its tune. That’s one of the things researchers have learned recently by eavesdropping on whales in several parts of the world and listening for changes in their pattern and pitch. Together, the new studies suggest that whales are not just whistling in the water, but constantly evolving a form of communication that we are only beginning to understand. Most whales and dolphins vocalize, but dolphins and toothed whales mostly make clicking and whistling sounds. Humpbacks, and possibly bowheads, sing complex songs with repeated patterns, said Michael Noad, an associate professor in the Cetacean Ecology and Acoustics Laboratory at the University of Queensland in Australia. Birds may broadcast their social hierarchy among song-sharing populations by allowing the dominant bird to pick the playlist and patterns. But how and why whales pass song fragments across hundreds of miles, and to thousands of animals, is far more mysterious. The biggest question is why whales sing at all. “The thing that always gets me out of bed in the morning is the function of the song,” Dr. Noad said. “I find humpback song fascinating from the point of view of how it’s evolved.” The leading hypothesis is that male humpbacks — only the males sing — are trying to attract females. But they may also switch tunes when another male is nearby, apparently to assess a rival’s size and fitness, said Dr. Noad, who was the senior author of one of four new papers on whale songs. © 2019 The New York Times Company

Keyword: Animal Communication; Sexual Behavior
Link ID: 25850 - Posted: 01.09.2019

By Kelly Servick In the animal world, monogamy has some clear perks. Living in pairs can give animals some stability and certainty in the constant struggle to reproduce and protect their young—which may be why it has evolved independently in various species. Now, an analysis of gene activity within the brains of frogs, rodents, fish, and birds suggests there may be a pattern common to monogamous creatures. Despite very different brain structures and evolutionary histories, these animals all seem to have developed monogamy by turning on and off some of the same sets of genes. “It is quite surprising,” says Harvard University evolutionary biologist Hopi Hoekstra, who was not involved in the new work. “It suggests that there’s a sort of genomic strategy to becoming monogamous that evolution has repeatedly tapped into.” Evolutionary biologists have proposed various benefits to so-called social monogamy, where mates pair up for at least a breeding season to care for their young and defend their territory. When potential mates are scarce or widely dispersed, for example, forming a single-pair bond can ensure they get to keep reproducing. Neuroscientist Hans Hofmann and evolutionary biologist Rebecca Young at the University of Texas in Austin wanted to explore how the regulation of genes in the brain might have changed when a nonmonogamous species evolved to become monogamous. For example, the complex set of genes that underlie the ability to tolerate the presence of another member of one’s species presumably exists in nonmonogamous animals, but might be activated in different patterns to allow prolonged partnerships in monogamous ones. © 2018 American Association for the Advancement of Science

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 25847 - Posted: 01.08.2019

By Jocelyn Kaiser, Ann Gibbons In early 2017, epidemiologist Rory Collins at the University of Oxford in the United Kingdom and his team faced a test of their principles. They run the UK Biobank (UKB), a huge research project probing the health and genetics of 500,000 British people. They were planning their most sought-after data release yet: genetic profiles for all half-million participants. Three hundred research groups had signed up to download 8 terabytes of data—the equivalent of more than 5000 streamed movies. That's enough to tie up a home computer for weeks, threatening a key goal of the UKB: to give equal access to any qualified researcher in the world. "We wanted to create a level playing field" so that someone at a big center with a supercomputer was at no more of an advantage than a postdoc in Scotland with a smaller computer and slower internet link, says Oxford's Naomi Allen, the project's chief epidemiologist. They came up with a plan: They gave researchers 3 weeks to download the encrypted files. Then, on 19 July 2017, they released a final encryption key, firing the starting gun for a scientific race. Within a couple of days, one U.S. group had done quick analyses linking more than 120,000 genetic markers to more than 2000 diseases and traits, data it eventually put up on a blog. Only 60,000 markers had previously been tied to disease, says human geneticist Eric Lander, president and director of the Broad Institute in Cambridge, Massachusetts. "[They] doubled that in a week." © 2018 American Association for the Advancement of Science

Keyword: Genes & Behavior; Depression
Link ID: 25841 - Posted: 01.05.2019

By Philippa Roxby Health reporter, BBC News Every year, there are always more baby boys than girls born in England and Wales. Fact. Why? Since records began in 1838, the cries of babies born every year have been predominately male. In not one year, stretching back to the start of Queen Victoria's reign, have girls outnumbered boys at birth. In 2017, in England and Wales, for example, there were 348,071 live male births and 331,035 live female births - a difference of roughly 17,000. And that higher tally of males compared to females born each year is a pattern that has repeated itself for nearly 180 years. In fact, a ratio of roughly 105 male births for every 100 female ones is generally seen as natural and normal. It is fairly consistent around the world, although in some countries like China and India the gap is wider because male offspring are more desirable. More surprisingly, it is a ratio that has been known about since the 17th Century. But why this ratio exists is not yet completely understood - although there are several theories. The first theory is an evolutionary one which says that in order to have an equal number of males and female in adulthood, there have to be slightly more males born. That is because being a male is a dangerous thing. Males are more likely than females to die in childhood and at all stages of life - from accidents, taking risks, suicide and from health problems. © 2018 BBC

Keyword: Sexual Behavior
Link ID: 25821 - Posted: 12.26.2018

By Katharine Q. Seelye Eleanor Emmons Maccoby, a distinguished psychologist and a pioneer in the field of gender studies who was the first woman to head the Stanford University psychology department, died on Dec. 11 in Palo Alto, Calif. She was 101. Her death, at a retirement community, was confirmed by her son, Mark, who said the cause was pneumonia. Dr. Maccoby, whom the American Psychological Association listed among the 100 most eminent psychologists of the 20th century, conducted pathbreaking research in child development and gender studies. She explored a wide range of topics, including interactions between parent and child and the effect of divorce on children. But the overarching themes of her long career were the differences between the sexes and how they develop. These were the subjects of two of her most significant books: “The Psychology of Sex Differences” (1974) and “The Two Sexes: Growing Up Apart, Coming Together” (1998). “She advanced our understanding of how girls and boys develop the characteristics that we think of as boy things and girl things,” Dr. John H. Flavell, a psychology professor emeritus at Stanford, said in a telephone interview. The answer involved a complex combination of biological, cognitive and social factors, including the dynamic in which children learn from other children. Dr. Maccoby did not initially consider herself a feminist. But she was gradually awakened by slights along the way, like being not allowed to enter the Faculty Club at Harvard through its front entrance, which was reserved for men, even though she was a member. Asked in a video interview in 2013 how she became interested in gender issues, she replied, “We lived it.” © 2018 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 25817 - Posted: 12.23.2018

By Leslie Nemo If you came across California mice in the wild, you wouldn’t hear a thing. Their jabber is ultrasonic—humans hear it only when it's slowed to five percent its original speed. But that’s when the imperceptible squeaks morph into a vocal range that’d put Mariah Carey to shame. Mice, you see, regularly vocalize to communicate in many different situations—which researchers did not know until recently. “It’s an under-appreciated part of biology of one of most diverse groups of mammals,” says Matina Kalcounis-Rueppell, a professor of biology at University of North Carolina, Greensboro who discovered about a decade ago that these mice vocalize. These sounds range from coos to startling barks. New research published in Frontiers in Ecology and Evolution shows that when these monogamous mice are separated from their mate and then reunited, the animals sometimes don’t handle it well—revealing a new side to their social lives and behavior. Here are some of the mouse calls recorded by Josh Pultorak, who recently earned his PhD with principal investigator Catherine Marler at the University of Wisconsin-Madison in the course of this research. The first sounds, short tweets, are considered friendly, and the most common. The second, slightly longer calls appear when the mice are getting “lovey-dovey”, says Pultorak. The third whale-like yelps are also friendly and connote a strengthening relationship.

Keyword: Sexual Behavior; Animal Communication
Link ID: 25791 - Posted: 12.17.2018

By Tom Garlinghouse Male and female bees may look similar, but they have dramatically different dining habits, according to a new study. Despite both needing nectar to survive, they get this nutrient from different flowers—so different, in fact, that males and females might as well belong to separate species. To make the find, researchers spent 11 weeks observing the foraging habits of 152 species of bees in several flower-rich New Jersey fields. Then they brought the insects—nearly 19,000 in all—back to the lab and meticulously identified their species and sex. Males and females rarely drank nectar from the same type of flower, the team will report in Animal Behaviour. Using a statistical test the researchers found that male and female bee diets overlap significantly less than would be expected at random. © 2018 American Association for the Advancement of Science

Keyword: Sexual Behavior
Link ID: 25776 - Posted: 12.12.2018

By Elizabeth Pennisi Anyone who has tried to whisper sweet nothings into their lover’s ear while standing on a noisy street corner can understand the plight of the túngara frog. A tiny amphibian about the size of a U.S. quarter, the male Physalaemus pustulosus has had to make its call more complex to woo mates when they move from the forest to the city. Now, researchers have found that female túngara frogs from both the country and the city prefer these mouthy city slickers. Biologists have long studied túngara frog courtship, demonstrating that visual signals and calls by themselves are unattractive to females but together are a winning combination, and that a female’s decision to mate depends on the context. Now, researchers have recorded the calls of male frogs living in cities, small towns, and forests across Panama. As they played the calls back, they counted the females, frog-eating bats, and frog-biting insects lured in by each call. Then they transplanted forest-dwelling frogs to the city and city dwellers to the forest to see how females there reacted to their calls. Finally, in the lab, they tested female preference for each call. Males living in cities and towns called more frequently and had more complex calls—with louder “chucks” interspersed in the whine—than forest frogs, the team reports today in Nature Ecology & Evolution. When they were moved into the country, they simplified their calls; but when their country cousins were brought to the big city, they couldn’t make the switch, and kept singing simply. When the researchers played back the calls to females, the females preferred more complex calls, even if the female herself was from the country, they reported. © 2018 American Association for the Advancement of Science

Keyword: Animal Communication; Sexual Behavior
Link ID: 25769 - Posted: 12.11.2018

Laura Sanders The uterus is best known for its baby-growing job. But the female organ may also have an unexpected role in memory, a study in rats suggests. The results, published online December 6 in Endocrinology, counter the idea that the nonpregnant uterus is an extraneous organ. That may have implications for the estimated 20 million women in the United States who have had hysterectomies. In the study, female rats either underwent removal of the uterus, ovaries, both organs or neither. Six weeks after surgery, researchers led by behavioral neuroscientist Heather Bimonte-Nelson of Arizona State University in Tempe began testing the rats on water mazes with platforms that were hidden just below the surface. Compared with the other groups, rats that lacked only a uterus were worse at remembering where to find the platforms as the tests turned progressively harder. The results suggest that signals that go from the uterus to the brain are somehow involved in remembering multiple bits of information at the same time. Rats lacking just a uterus had differences in their hormone levels, too, even though these rats kept their hormone-producing ovaries. Researchers have known for decades that hormones released by the ovaries can influence the brain. But finding that the uterus on its own can influence memory is a surprise, says neuroendocrinologist Victoria Luine of Hunter College of the City University of New York. Because many women have their uteruses removed but keep their ovaries, “this revelation brings up some interesting questions to explore.” |© Society for Science & the Public 2000 - 2018

Keyword: Learning & Memory; Hormones & Behavior
Link ID: 25757 - Posted: 12.07.2018

By Daphna Joel and Cordelia Fine In 17th and 18th century Europe, the rise of egalitarian ideals created the need for a scientific account of women’s inferior status. Thus was born gender biological complementarity — the notion that, as historian of science Londa Schiebinger explains in The Mind Has No Sex, “Women were not to be viewed merely as inferior to men but as fundamentally different from, and thus incomparable to, men.” It has been with us in one way or another, roping in science to explain the gender status quo, ever since. At its core is the persistent belief that men’s and women’s natures can be usefully and meaningfully carved into two categories or “natural kinds,” that are distinct, timeless, and deeply biologically grounded. Today’s version of this idea continues a centuries long quest to find the source of this hypothesized divergence in abilities, preferences, and behavior in the brain: You can find this notion at work, for instance, in popular books like John Gray’s “Men Are from Mars, Women Are from Venus” in the 1990s, Louann Brizendine’s “The Female Brain” and “The Male Brain” the following decade, and last year’s “Results at the Top: Using Gender Intelligence to Create Breakthrough Growth” by Barbara Annis and Richard Nesbitt. But a version of the same assumption is also sometimes subtly present in scientific research. Consider, for example, Cambridge University psychologist Simon Baron-Cohen’s influential Empathizing-Systemizing theory of brains and the accompanying “extreme male brain” theory of autism. This presupposes there is a particular “systemizing” brain type that we could meaningfully describe as “the male brain,” that drives ways of thinking, feeling, and behaving that distinguish the typical boy and man from the typical “empathizing” girl and woman. © 2018 The New York Times Company

Keyword: Sexual Behavior
Link ID: 25747 - Posted: 12.04.2018