Links for Keyword: Sexual Behavior

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By Alice Klein It is pest control without poison. A new type of bait that stops rats from having babies is helping to tackle infestations in several US cities. The bait – known as ContraPest – was approved by the US Environmental Protection Agency last August. It makes rats infertile by triggering early menopause in females and impairing sperm production in males. There are no side effects and the rats eventually die of natural causes. The technique is considered more benign than other control strategies being investigated, such as gene drive, which can be used to spread infertility genes through pest populations. A recent report by the US National Academies of Sciences warned that gene drive could have unforeseen consequences. The first field trial of ContraPest, conducted in the New York City Subway in 2013, halved the resident rat population in three months. Two more trials have now been completed in the US – one at a large-scale farm and one in an urban area – both in East Coast cities. Rat numbers at the farm fell by one-third over three months. In the urban area, population growth was suppressed during the peak breeding season so that the population expanded at only one-third the expected rate. “You’ll never wipe out rats completely – they’re too smart,” says Brandy Pyzyna from SenesTech, the biotechnology company in Arizona that developed the bait. © Copyright Reed Business Information Ltd.

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 23583 - Posted: 05.06.2017

By Jef Akst Drawing on data on organ-, tissue-, and individual-specific gene expression from the Genotype-Tissue Expression (GTex) Portal, Shmuel Pietrokovski and Moran Gershoni of the Weizmann Institute of Science in Israel developed a comprehensive map of genes that are differentially expressed in men and women. The study was inspired by work the duo conducted several years ago, in which they found that mutations accumulated in genes for sperm formation likely because they were expressed only in men, not in women. As a result, even harmful mutations would only cause problems to half the population; unaffected women would continue to pass on the defective gene without any hit to their fitness. To explore whether other genes expressed differentially between the sexes might be similarly subject to mutation accumulation, Pietrokovski and Gershoni examined some 20,000 protein-coding genes, of which around 6,500 were expressed more in one sex than the other somewhere in the body. And sure enough, selection was effectively weaker in these genes, leading to the pile up of deleterious mutations. “The more a gene was specific to one sex, the less selection we saw on the gene,” Gershoni told the institute’s news publication, Weizmann Wonder Wander, this week (May 3). “The basic genome is nearly the same in all of us, but it is utilized differently across the body and among individuals,” he continued. “Thus, when it comes to the differences between the sexes, we see that evolution often works on the level of gene expression.” © 1986-2017 The Scientist

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23581 - Posted: 05.06.2017

By RICHARD O. PRUM In a mossy forest in the western Andes of Ecuador, a small, cocoa-brown bird with a red crown sings from a slim perch. Bip-Bip-WANNGG! It sounds like feedback from an elfin electric guitar. Three rival birds call back in rapid response. These male club-winged manakins are showing off to attract female mates. Their strange songs are associated with an even stranger movement. Instead of opening their beaks, they flick their wings open at their sides to make the Bips, and then snap their wings up over their backs to produce the extraordinary WANNGG. They are singing with their wings, and their potential mates seem to find the sound very alluring. This is an evolutionary innovation — a whole new way to sing. But the evolutionary mechanism behind this novelty is not adaptation by natural selection, in which only those who survive pass on their genes, allowing the species to become better adapted to its environment over time. Rather, it is sexual selection by mate choice, in which individuals pass on their genes only if they’re chosen as mates. From the peacock’s tail to the haunting melodies of the wood thrush, mate choice is responsible for much of the beauty in the natural world. Most biologists believe that these mechanisms always work in concert — that sex appeal is the sign of an objectively better mate, one with better genes or in better condition. But the wing songs of the club-winged manakin provide new insights that contradict this conventional wisdom. Instead of ensuring that organisms are on an inexorable path to self-improvement, mate choice can drive a species into what I call maladaptive decadence — a decline in survival and fecundity of the entire species. It may even lead to extinction. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23580 - Posted: 05.06.2017

Jon Brooks Max, age 13, is agender — neither male nor female. When referring to Max, you don't use "he" or "she;" you use "they." Once strictly a pronoun of the plural variety, "they" is now doing double duty as singular, too — referring to individuals, like Max, who do not see gender as an either/or option. (NPR agreed not to use Max's last name, because the family feared the sort of online threats that have been made to other transgender families.) If the whole he/she pronoun thing feels awkward to you, Max is sympathetic — and patient. 'We are seeing more and more kids saying, 'You know what? What's with this either-or business? What's with this boy-girl and you have to fit in one box or the other?' " Diane Ehrensaft, psychologist, Child and Adolescent Gender Center, UCSF Benioff Children's Hospital "I can't expect anyone to use the right pronouns for me because it's not a thing that people know," Max tells me. "It's been great being myself, but it's also been really hard for people to get it, and for even family to get pronouns and stuff." We're talking in Max's room at home, where posters on the wall showcase the teen's love of theater: Peter Pan, Tarzan, The Pirates of Penzance. Max is old enough now to enjoy using make-up — blush, foundation, lipstick — but still young enough to enjoy going with their mom to see "Willy Wonka & The Chocolate Factory." (The review from Max: Gene Wilder's great!) From these surroundings, you wouldn't think the room's occupant is someone who has already poked and prodded at the most fundamental sense of who they are. Really, this is just a kid's room. © 2017 npr

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23562 - Posted: 05.02.2017

By Debra W. Soh The reasons behind why people are gay, straight, or bisexual have long been a source of public fascination. Indeed, research on the topic of sexual orientation offers a powerful window into understanding human sexuality. The Archives of Sexual Behavior recently published a special edition devoted to research in this area, titled “The Puzzle of Sexual Orientation.” One study, conducted by scientists at the University of Lethbridge in Alberta, Canada, offers compelling, cross-cultural evidence that common genetic factors underlie same-sex, sexual preference in men. In southern Mexico, individuals who are biologically male and sexually attracted to men are known as muxes. They are recognized as a third gender: Muxe nguiiu tend to be masculine in their appearance and behavior, while muxe gunaa are feminine. In Western cultures, they would be considered gay men and transgender women, respectively. Several correlates of male androphilia — biological males who are sexually attracted to men — have been shown across different cultures, which is suggestive of a common biological foundation among them. For example, the fraternal birth order effect—the phenomenon whereby male androphilia is predicted by having a higher number of biological older brothers—is evident in both Western and Samoan cultures. Interestingly, in Western society, homosexual men, compared with heterosexual men, tend to recall higher levels of separation anxiety — the distress resulting from being separated from major attachment figures, like one’s primary caregiver or close family members. Research in Samoa has similarly demonstrated that third-gender fa’afafine—individuals who are feminine in appearance, biologically male, and attracted to men—also recall greater childhood separation anxiety when compared with heterosexual Samoan men. Thus, if a similar pattern regarding separation anxiety were to be found in a third, disparate culture—in the case, the Istmo region of Oaxaca, Mexico—it would add to the evidence that male androphilia has biological underpinnings. © 2017 Scientific American

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory, Learning, and Development
Link ID: 23540 - Posted: 04.26.2017

By CATHERINE SAINT LOUIS In her 30s, Sophie Marat, now 42, used to record herself reading poetry aloud, then play it back to hear if she sounded like a woman. Ms. Marat, who is transgender, had spent years trying to remake her voice in private by speaking in a higher pitch but ultimately felt that her efforts were hopeless. “I was feeling like changing my voice to match my gender identity was almost impossible,” she said. “It was terrible.” Ms. Marat’s transition from male to female has been a gradual evolution. She had come out to friends and family back home in Mexico, then began to wear skirts to work as a software engineer in Manhattan. Still, her confidence would falter with everyday tasks like ordering takeout. “It was really painful to speak on the phone,” she said, “because they would reply, ‘O.K., sir.’” That was before she started her weekly sessions with a voice therapist at New York University’s speech-language-hearing clinic, one of a growing number of programs that cater to transgender clients seeking to retrain their voices. Just as some transgender women and men choose to take hormones or have surgery, or choose neither, some seek to feminize or masculinize their voices. Many say they want a voice that matches their appearance or that the change allows them to escape unwanted attention. There’s also a growing recognition among health professionals who have transgender patients that altering one’s voice can improve quality of life and reduce distress. After eight months, she had raised her pitch, worked on moving her resonance forward and finishing phrases with an open ending, rather than bluntly. “This isn’t just a sidebar,” said Sandy Hirsch, a Seattle-based speech language pathologist who was a co-author of the pioneering textbook on transgender voice and communication therapy. “It’s an integral part of care for transgender people as they transition.” © 2017 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Brain Asymmetry, Spatial Cognition, and Language
Link ID: 23539 - Posted: 04.26.2017

Carl Zimmer The oldfield mouse doesn’t seem extraordinary. With soulful black eyes and tiny teacup ears, the rodent lives a humdrum life scurrying about meadows and beaches in the Southeast. But field biologists have long known that when it comes to sex and family life, this mouse is remarkable: Peromyscus polionotus is monogamous — an exception among mammals — and a solicitous parent. Fathers and mothers will dig burrows together and build elaborate nests when pups are on the way; after they’re born, the father will help tend to the pups, retrieving them when they fall out of the nest, licking them, and huddling to keep them warm. In a pioneering study published on Wednesday in the journal Nature, researchers at Harvard University identified a genetic basis for this distinctive behavior. It is the first time that scientists have linked DNA to variations in parenting habits among mammals. Dieter Lukas, an evolutionary biologist at the University of Cambridge who was not involved in the research, hailed the study as a sophisticated tour de force, saying that uncovering these links “is like designing a tool to follow individual threads through a large colorful tapestry.” The findings may one day help scientists make sense of how human couples bond and care for their children. Mammals share many of the genes governing the production of hormones and neurotransmitters in the brain. Variations in how they function may explain why most species are promiscuous, why a few are monogamous — and why some, like humans, are somewhere in between. “We can go from the bottom up and build our knowledge base, and then ask questions about human biology,” said Gene E. Robinson, a biologist at the University of Illinois who was not involved in the new work. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 23516 - Posted: 04.20.2017

by Claire Lehmann and Debra W Soh “Neurosexism,” “populist science,” “neurotrash,” the problem with using terms like these to describe scientific investigations of sex differences is that their use may be interpreted as hostile. “Not fair!” claim the espousers of these terms, who argue that they only ever use such terms for pseudoscience and media distortions, not robust and replicable studies. In a recent op-ed for The Guardian, Cordelia Fine—the author who coined the term “neurosexism”—together with Rebecca Jordan-Young, argue that they have never been prima facie opposed to sex differences research. Their only concern is that of scientific rigour. In 2005, the British philosopher Nicholas Shackel proposed the term “Motte and Bailey Doctrine” for this type of argumentative style. Taking the name of the castle fortification, the “motte” is strong and is built high on an elevated patch of land and is easy to defend. By contrast, the “bailey” is built on lower, more exposed ground, and is much more difficult to defend from attacks. Shackel used this metaphor to describe a common rhetorical trap used by postmodern academics, where a controversial proposition is put forward (a “bailey”) but is then switched for an uncontroversial one (a “motte”) when faced with criticism. In this case, the controversial position that has been proposed by authors such as Fine and Jordan-Young is that the scientific investigation of sex differences reinforce and legitimize harmful and sexist stereotypes about women. The uncontroversial proposition is that their concern is simply one of “[ensuring] the [maximum possible contribution] of neuroimaging research.” © 2017 Quillette

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23507 - Posted: 04.19.2017

By Michael Price Do the anatomical differences between men and women—sex organs, facial hair, and the like—extend to our brains? The question has been as difficult to answer as it has been controversial. Now, the largest brain-imaging study of its kind indeed finds some sex-specific patterns, but overall more similarities than differences. The work raises new questions about how brain differences between the sexes may influence intelligence and behavior. For decades, brain scientists have noticed that on average, male brains tend to have slightly higher total brain volume than female ones, even when corrected for males’ larger average body size. But it has proved notoriously tricky to pin down exactly which substructures within the brain are more or less voluminous. Most studies have looked at relatively small sample sizes—typically fewer than 100 brains—making large-scale conclusions impossible. In the new study, a team of researchers led by psychologist Stuart Ritchie, a postdoctoral fellow at the University of Edinburgh, turned to data from UK Biobank, an ongoing, long-term biomedical study of people living in the United Kingdom with 500,000 enrollees. A subset of those enrolled in the study underwent brain scans using MRI. In 2750 women and 2466 men aged 44–77, Ritchie and his colleagues examined the volumes of 68 regions within the brain, as well as the thickness of the cerebral cortex, the brain’s wrinkly outer layer thought to be important in consciousness, language, memory, perception, and other functions. © 2017 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 23478 - Posted: 04.11.2017

By Andy Coghlan “PRENATAL exposure to progesterone affects sexual orientation in humans”. A bold and unequivocal-sounding title for a scientific paper. And certainly important if true. But is it? The study claimed to show that women given extra progesterone during pregnancy, routinely prescribed to prevent miscarriage, bleeding or premature delivery, have children who are “29 per cent more likely” to later identify as bisexual. It would be a landmark finding, allowing us to also ground in biology the established social science contention that sexuality has more dimensions than straight and gay. We suspected that exposing a fetus to strong hormones can shape sexual orientation. But there are no animal models of sexual orientation, and doing this kind of experiment in humans would be deeply unethical. The next best thing would be a retrospective analysis looking at a birth cohort exposed to a specific hormone “in the wild”. And that’s what this study did. June Reinisch of the Kinsey Institute in Indiana and her colleagues trawled a public database containing records of more than 9000 pregnancies in Denmark between 1959 and 1961. They identified women who were given a progesterone-mimicking hormone by the trade name lutocyclin to prevent miscarriage. Lutocyclin did seem to have mild effects on sexual orientation: later in life, exposed individuals were five times more likely to self-identify as non-heterosexual, and were more likely to report relationships with the same sex, than unexposed controls. © Copyright Reed Business Information Ltd.

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23477 - Posted: 04.11.2017

Cordelia Fine and Rebecca Jordan-Young At a time when both science and feminism are under attack, there are welcome signs that neuroscience is showing new openness to critiques of research into sex differences. Mainstream journals increasingly publish studies that reveal how misleading assumptions about the sexes bias the framing of hypotheses, research design and interpretation of findings – and these critiques increasingly come with constructive recommendations, discussions and debates. For example, we, together with other colleagues, made recommendations in the peer-reviewed journal Frontiers in Human Neuroscience on best practice in sex/gender neuroscience. Some of the errors and traps we identified included human neuroimaging studies with small sample sizes, and the common “snapshot” approach, which interprets neural associations with sex as a matter of timeless and universal male and female essences, without taking seriously the fact that biological associations might as easily be the effect of social differences as the cause of them. For example, a study reporting female-male differences in spatial processing should take into account that women and men have different life experiences, on average, that can build such skills – such as practice with aiming at targets that comes from certain kinds of sports and video games. We also expressed concern about studies that draw on and reinforce stereotypes, even as they slip and slide regarding specific predictions about sex differences in the brain, and what findings might mean for how women and men think, feel, and behave.

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23465 - Posted: 04.08.2017

Erin Ross The sex of a sea lamprey may be determined by how fast it grows as a larva. Sex is determined by chromosomes in mammals and by temperature in many reptiles. But for sea lampreys — eel-like creatures that dine on blood — the growth rate of their larvae seems to control whether they are male or female. They are the first creatures known to undergo sex determination in this way. Researchers know next to nothing about sex determination in sea lampreys (Petromyzon marinus) and have long been puzzled by the observation that some adult populations are mostly male, and others female. The fish begin their lives as larvae with undifferentiated sexual organs. After a year or so, they develop gonads, and after a few more years — the timing can vary — they metamorphose into adult sucker-mouthed parasites. A team led by biologist Nick Johnson, at the US Geological Survey in Millersburg, Michigan, identified lamprey habitats in and near streams leading to the Great Lakes. Some areas were productive, with lots of food, whereas others were unproductive sites with little food. After taking measures to ensure no wild lamprey were present, they released between 1,500 and 3,000 wire-tagged larval lamprey into each of the study sites. The researchers recaptured the tagged lamprey and checked their sex after the larvae had metamorphosed into adults and migrated upstream. They found that lamprey in productive streams with lots of food were larger, reached maturity earlier and were more likely to be female. But in unproductive sites, smaller, male lamprey dominated, Johnson’s team reports in a paper published on 29 March in Proceedings of the Royal Society B1. © 2017 Macmillan Publishers Limited

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23427 - Posted: 03.30.2017

By Kate Yandell In a 1971 paper published in Science, biologist Roger Payne, then at Rockefeller University, and Scott McVay, then an administrator at Princeton University, described the “surprisingly beautiful sounds” made by humpback whales (Megaptera novaeangliae; Science, 173:585-97). Analyzing underwater recordings made by a Navy engineer, the duo found that these whale sounds were intricately repetitive. “Because one of the characteristics of bird songs is that they are fixed patterns of sounds that are repeated, we call the fixed patterns of humpback sounds ‘songs,’” they wrote. OCEAN SONGS: Humpback whales make diverse, broadband sounds that travel miles through the ocean. Their function, however, remains somewhat murky.PLOS ONE, dx.doi.org/10.1371/journal.pone.0079422, 2013 It’s now clear that, in addition to simpler calls, several baleen whale species—including blue, fin, and bowhead—make series of sounds known as song. Humpback song is the most complex and by far the best studied. Units of humpback songs form phrases, series of similar phrases form themes, and multiple themes form songs. All the males in a given population sing the same song, which evolves over time. When whale groups come into contact, songs can spread. But why do whales sing? “The short answer is, we don’t know,” says Alison Stimpert, a bioacoustician at Moss Landing Marine Laboratories in California. Humpback songs are only performed by males and are often heard on breeding grounds, so the dominant hypothesis is that these songs are a form of courtship. The quality of a male’s performance could be a sign of his fitness, for example. But female whales do not tend to approach singing males. Alternatively, whale researchers have proposed that the male whales sing to demarcate territory or to form alliances with other males during mating season. © 1986-2017 The Scientist

Related chapters from BN8e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 23419 - Posted: 03.29.2017

By Sam Wong It takes brains to choose a good partner. In one of the first experiments to look at the cognitive demands of choosing a mate, female guppies with big brains showed a preference for more colourful males, while those with smaller brains showed no preference. In guppies, like most animals, females are choosy about who to mate with, since they invest more in their offspring than males, which don’t help care for them. They tend to prefer males with striking colour patterns and big tails, traits that have been linked to good foraging ability and health. By choosing a male with these qualities, female guppies give their offspring a good chance of inheriting the same useful traits. Despite this, females often go on to make different choices. Alberto Corral López and colleagues at Stockholm University wanted to find out if brain size could account for this. Corral López and his team tested 36 females bred to have large brains, 36 bred to have small brains, and 16 females similar to guppies found in the wild. Previous studies have shown that large-brained guppies perform better in cognitive tests, suggesting that they are smarter. Each female was given the opportunity to associate with two males, one more colourful than the other. Females are known to spend more time close to males they would prefer to mate with, so the team timed how long they spent with each male. © Copyright Reed Business Information Ltd

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23394 - Posted: 03.23.2017

Cris Ledón-Rettig Picture a lion: The male has a luxuriant mane, the female doesn’t. This is a classic example of what biologists call sexual dimorphism – the two sexes of the same species exhibit differences in form or behavior. Male and female lions pretty much share the same genetic information, but look quite different. We’re used to thinking of genes as responsible for the traits an organism develops. But different forms of a trait – mane or no mane – can arise from practically identical genetic information. Further, traits are not all equally sexually dimorphic. While the tails of peacocks and peahens are extremely different, their feet, for example, are pretty much the same. Understanding how this variation of form – what geneticists call phenotypic variation – arises is crucial to answering several scientific questions, including how novel traits appear during evolution and how complex diseases emerge during a lifetime. So researchers have taken a closer look at the genome, looking for the genes responsible for differences between sexes and between traits within one sex. The key to these sexually dimorphic traits appears to be a kind of protein called a transcription factor, whose job it is to turn genes “on” and “off.” In our own work with dung beetles, my colleagues and I are untangling how these transcription factors actually lead to the different traits we see in males and females. A lot of it has to do with something called “alternative gene splicing” – a phenomenon that allows a single gene to encode for different proteins, depending on how the building blocks are joined together. © 2010–2017, The Conversation US, Inc.

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23380 - Posted: 03.21.2017

By Michael Price The objects and people children play with as early as toddlerhood may provide clues to their eventual sexual orientation, reveals the largest study of its kind. The investigation, which tracked more than 4500 kids over the first 15 years of their lives, seeks to answer one of the most controversial questions in the social sciences, but experts are mixed on the findings. “Within its paradigm, it’s one of the better studies I’ve seen,” says Anne Fausto-Sterling, professor emerita of biology and gender studies at Brown University. The fact that it looks at development over time and relies on parents’ observations is a big improvement over previous studies that attempted to answer similar questions based on respondents’ own, often unreliable, memories, she says. “That being said … they’re still not answering questions of how these preferences for toys or different kinds of behaviors develop in the first place.” The new study builds largely on research done in the 1970s by American sex and gender researcher Richard Green, who spent decades investigating sexuality. He was influential in the development of the term “gender identity disorder” to describe stress and confusion over one’s sex and gender, though the term—and Green’s work more broadly—has come under fire from many psychologists and social scientists today who say it’s wrong to label someone’s gender and sexuality “disordered.” In the decades since, other studies have reported that whether a child plays along traditional gender lines can predict their later sexual orientation. But these have largely been criticized for their small sample sizes, for drawing from children who exhibit what the authors call “extreme” gender nonconformity, and for various other methodological shortcomings. © 2017 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory, Learning, and Development
Link ID: 23347 - Posted: 03.11.2017

If I was the late Andy Rooney, I’d say “You know what really bothers me? When science shows some facts about nature, and then someone rejects those facts because they’re inconvenient or uncomfortable for their ideology.” Indeed, when people ignore such inconvenient truths, it not only makes their cause look bad, but can produce palpable harm. Case in point: the damage that the Russian charlatan-agronomist Lysenko did to Soviet agriculture under Stalin. Rejecting both natural selection and modern genetics, Lysenko made all sorts of wild promises about improving Soviet agriculture based on bogus treatment of plants that would supposedly change their genetics. It not only didn’t work, failing to relieve Russia of its chronic famines, but Lyesnko’s Stalin-supported resistance to modern (“Western”) genetics led to the imprisonment and even the execution of really good geneticists and agronomists like Niklolia Vavilov. The ideological embrace of an unevidenced but politically amenable view of science set back Russian genetics for decades. Other cases in point: the denial of evolution by creationists, and of anthropogenic global warming by conservatives. I needn’t belabor these. But the opposition to research on group and sex differences continues. One of its big exponents is the author Cordelia Fine, who has written two books with the explicit aim of showing that there are no reliably accepted evolved and biological differences in behavior between men and women. I read her first book, Delusions of Gender, and found it a mixed bag: some of her targets did indeed do bad science, and she properly called them out; but the book was also tendentious, and wasn’t objective about other studies. I’m now about to read her second book, Testosterone Rex: Myths of Sex, Science, and Society. Judging from the reviews, which have been positive, it’s just as much a polemic as the first book, and has an ideological aim.

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23336 - Posted: 03.10.2017

Nicola Davis The mystery of why sheep get horny in the winter might have been solved, according to new research. Scientists say they have uncovered the key to the mechanism by which changes in the length of the day prompt certain animals to begin breeding, trigger the growth of horns and even change the thickness of their coat. The findings, the team add, could help farmers tinker with the timing of the lambing season. “Now we know what that link is we can start to understand how it can be controlled,” said David Bates, professor of oncology at the University of Nottingham and co-author of the research. It has long been known that changes in animals’ fertility over the seasons is linked to melatonin – a hormone released at night from the pineal gland in the brain. This hormone acts on another gland, the pituitary, affecting the levels of various sex hormones it produces. With the onset of fertility in sheep linked to longer periods of melatonin production, winter is the season for ovine Casanovas. But there is a puzzle. The region of the pituitary gland that detects melatonin is separate to the region that produces sex hormones. As a result, scientists had been baffled as to how melatonin ends up affecting the onset of fertility. “No-one has been able to find what the link is,” said Bates. Now Bates and colleagues from the University of Bristol say they have the answer. Writing in the journal PNAS, the team reveal the missing link is a protein, known as vascular endothelial growth factor, which is made in the region of the pituitary gland that detects melatonin. © 2017 Guardian News and Media Limited

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 23322 - Posted: 03.07.2017

By The Scientist Staff For thousands of years, people have appreciated birdsong as one of nature’s most melodic sounds. And for at least a few centuries, researchers have been talking about—and analyzing— birdsong, some attaching the label “music” to the avian behavior. In the mid-17th century, for example, German scholar Athanasius Kircher transcribed bird song with musical notation. Whether singing avian species hear their calls in a musical sense is, of course, anybody’s guess. But still today, it’s fairly uncontroversial to speak about bird vocalizations using terms such as “song” and “music.” Around the animal kingdom, several nonavians also produce sounds that are sometimes discussed using a musical vocabulary. Whale songs echo through the ocean for hundreds of miles, while frogs and crickets chorus on warm summer nights throughout much of the world. The stringency of the criteria for earning a label such as song varies by taxon, however. Birds, whales, mice, and even bats have a vocal repertoire that includes songs and simpler calls, while any insect or fish that produces sound for the sake of communication is considered, at least by some, to be “singing”—though no scientist seriously compares these species’ chirps and grunts to birdsong. Semantics aside, more and more tonal or cadenced animal communication signals are attracting the attention of researchers. Technological advancements have enabled the study of mouse and bat calls that are broadcast in the ultrasonic range, as well as of the love songs of fruit flies, which vibrate their wings to produce sound within the frequency range of human hearing, but do so a million times more quietly than our ears can detect. And research continues to delve into the musical skills of diverse bird species that have long been recognized for their singing prowess, confirming that there is an overlap between the genes and brain areas involved in bird and human vocal learning. © 1986-2017 The Scientist

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Brain Asymmetry, Spatial Cognition, and Language
Link ID: 23321 - Posted: 03.07.2017

by Laura Sanders Amid a flurry of cabinet appointments and immigration policies, the Trump administration has announced one thing it will not do: pursue policies that protect transgender children in public schools. The Feb. 22 announcement rescinds Obama administration guidelines that, among other protections, allow transgender kids to use bathrooms and participate in sports that correspond with their genders, and to be called by their preferred names and pronouns. In a Feb. 23 news briefing, White House press secretary Sean Spicer said that this is a states’ rights issue. “States should enact laws that reflect the values, principles, and will of the people in their particular state,” he said. “That's it, plain and simple.” But this “plain and simple” move could be quite dangerous, even deadly, science suggests. Transgender children, who are born one biological sex but identify as the other, already face enormous challenges as they move through a society that often doesn’t understand or accept them. Consider this: Nearly half (46.5 percent) of young transgender adults have attempted suicide at some point in their lives, a recent survey of over 2,000 people found. Nearly half. For comparison, the attempted suicide rate among the general U.S. population is estimated to be about 4.6 percent. What’s more, a 2015 study in the Journal of Adolescent Health found that transgender youth are two to three times as likely as their peers to suffer from depression and anxiety disorders, or to attempt suicide or harm themselves. These troublesome stats, based on a sample of 180 transgender children and young adults in Boston ages 12 to 29, applied equally to those who underwent male-to-female transitions and those who underwent female-to-male transitions. © Society for Science & the Public 2000 - 2017.

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 23297 - Posted: 03.01.2017