By Victoria Gill Science reporter, BBC Nature Night-time in the Jurassic forest was punctuated by the unmistakable sound of chirping bush crickets. This is according to scientists who have reconstructed the song of a cricket that chirped 165 million years ago. A remarkably complete fossil of the prehistoric insect enabled the team to see the structures in its wings that rubbed together to make the sound. The international team report their findings in the journal PNAS. Scientists from the US and China discovered the tiny fossil and named their newly discovered species Archaboilus musicus , because the music-making structures in its body were so clearly visible. When insect expert Dr Fernando Montealegre Zapata, from the University of Bristol, found out that his colleagues had such a remarkable fossil, he was keen to see it. "I was very surprised," he told BBC Nature, "because those [structures] are very very small - at the microscopic level." Dr Zapata studies sound production and communication in living insects, working out how the musical instruments contained in many insects' bodies produce a particular sound, and exactly how that sound is made. He immediately asked the question: "Could we reproduce the sounds [this insect made] from that fossil?" BBC © 2012

Related chapters from BP6e: 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: 16350 - Posted: 02.07.2012

by Michael Marshall In one of philosophy's greatest facepalm moments, the normally quite intelligent Arthur Schopenhauer wrote that "women are defective in the powers of reasoning and deliberation". If you find it hard to believe that a well-educated and original thinker could hold such a view, his essay Of Women leaves no doubt about it. Oddly enough, he never married. However, Schopenhauer might have had a point, if only he had been a three-spined stickleback living in Lake Mývatn in Iceland. In this one population, the males have brains much larger than those of the females. They are the only species known where there is such a big disparity between the two sexes' brains. What's surprising is that there aren't more animals like this. Species differ enormously in brain size, after all, and males and females often have different lifestyles that make different demands on their brains. Why do these few fish buck the trend? Most three-spined sticklebacks live in the sea and only visit fresh water to breed, but others – like the Mývatn population – spend all their lives in fresh water. Behavioural scientists have studied them for decades because of their elaborate mating rituals. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16341 - Posted: 02.04.2012

By ABIGAIL ZUGER, M.D. Science generally succeeds in bringing some order to human existence — except when it does just the reverse, imposing a structure that never quite fits properly no matter how much it is tweaked. Then it just accentuates the underlying chaos. The much-disputed, oft-revised manual of psychiatric diagnosis might serve as one illustration of this phenomenon; given that it runs to almost 1,000 pages, Hanne Blank gets a pat on the back for dispatching the equally murky entity of heterosexuality in fewer than 200, plus back matter. One can almost hear a chorus of experts in the many sciences of sex and gender muttering that her amusing, readable synthesis is a featherweight effort, simplistic and derivative. But for those not in the field but still in the game, as it were — readers never previously moved to reason from first principles exactly what it means to be a heterosexual or act like one — Ms. Blank darts from one intriguing, thought-provoking point to another. She is a self-described “independent scholar” in Baltimore with several volumes of erotica and a well-received history of the virgin to her credit. Is Ms. Blank herself a heterosexual? That question prompts the first of her looping mind games. She has had romantic relationships with women in the past — so, no, right? Now, though, she is in a stable, long-term romantic partnership with a man (so, yes, right?). But her partner has a complicated genome, with some ordinary male XY cells and some that have an XXY pattern, giving him a softer, more stereotypically feminine aspect than usual, despite standard-issue male genitalia. And suddenly that word, “heterosexual,” becomes less than the helpful, scientifically precise term one might wish for. © 2012 The New York Times Company

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16325 - Posted: 01.31.2012

By Joseph Castro, LiveScience Staff Writer Most people are familiar with the telltale squeak of a mouse scurrying out of their pantry, but scientists have long known that these aren’t the only noises house mice make. During courtship, the rodents also communicate in the ultrasonic frequency range, which sits beyond human hearing. Now, new research shows that these mating vocalizations are more than just your typical squeaks — they’re songs, not unlike those you’d expect to hear from courting birds. “It seems as though house mice might provide a new model organism for the study of song in animals," lead researcher Dustin Penn, an evolutionary biologist at the Veterinary University of Vienna in Austria, said in a statement. "Who would have thought that?" Over the last few years, Penn and his colleagues conducted a series of studies on the courtship vocalizations of house mice. In their initial research, published in the journal Animal Behavior in 2010, they caught wild male and female house mice and looked at the vocal nature of their courtship routines. They found that most of the male mice would start their ultrasonic calls the moment they caught the urine scent of a sexually mature female. When the researchers played these calls back to the females, they learned that the females could somehow tell the difference between the calls of their siblings and the calls of unrelated males — the females showed little interest in the squeaks of their brothers. © 2012 msnbc.com

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 16315 - Posted: 01.30.2012

By FRANK BRUNI BORN this way. That has long been one of the rallying cries of a movement, and sometimes the gist of its argument. Across decades of widespread ostracism, followed by years of patchwork acceptance and, most recently, moments of heady triumph, gay people invoked that phrase to explain why homophobia was unwarranted and discrimination senseless. Lady Gaga even spun an anthem from it. But is it the right mantra to cling to? The best tack to take? Not for the actress Cynthia Nixon, 45, whose comments in The New York Times Magazine last Sunday raised those very questions. For 15 years, until 2003, she was in a relationship with a man. They had two children together. She then formed a new family with a woman, to whom she’s engaged. And she told The Times’s Alex Witchel that homosexuality for her “is a choice.” “For many people it’s not,” she conceded, but added that they “don’t get to define my gayness for me.” They do get to fume, though. Last week some did. They complained that she represented a minority of those in same-sex relationships and that she had furthermore handed a cudgel to our opponents, who might now cite her professed malleability as they make their case that incentives to change, not equal rights, are what we need. © 2012 The New York Times Company

Related chapters from BP6e: 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: 16314 - Posted: 01.30.2012

By DIANE ACKERMAN WHAT’S the quickest way to a man’s heart? No, not through the chest wall with a knife. According to Mom wisdom, it’s a cozy meal, in a penumbra of pleasure that mingles the fragrant food with the cook. If men are anything like common fruit flies — and who’s to say they’re not at times; heaven knows women are — Mom was right. Anyway, that’s the romantic ploy of female fruit flies, for whom a dinner date is the ultimate rush. And rush it literally is, since they live only about 25 days and can’t afford to be shy. Still, the males need to be in the right mood, and the females are surprisingly picky and manipulative, given their short careers. Did I mention that some fruit flies have come-hither eyes? I don’t mean the dozens of mosaic facets, so evocative of hippie sunglasses, but the zingy psychedelic eye colors lab folk like to breed into them, the better to study mutant genes. As a Cornell grad student, I often stopped by the fetid biology lab to admire the eggplant-blackness of the abdomens, the spiky hairs, the gaudy prisms of the eyes — some apricot, some teal, some purple, some the brick-red of Ming vases. A favorite of biologists, fruit flies have it all — they’re prowling for mates within 12 hours of birth, they’re easy to raise and they can lay 100 eggs a day. Plus, they share most of our genes, including about 70 percent of those we’ve linked to such diseases as Parkinson’s and Alzheimer’s. © 2012 The New York Times Company

Related chapters from BP6e: 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: 16256 - Posted: 01.16.2012

by Jessica Hamzelou IT'S true - sex does change things, including the structure of rats' brains. And another thing - it really is different for males and females. There are several brain regions linked to sexual behaviour that differ in size between the sexes in humans and other mammals. To find out whether a region known to be bigger in males was altered by sex, Shinji Tsukahara and his colleagues at Saitama University near Tokyo, Japan, compared the brains of male rats who had never had sex before with their more experienced counterparts. They found that the number of spiny structures located at the neuronal synapses was significantly lower in rats that had copulated. Tsukahara, who presented the findings at the recent Society for Neuroscience meeting in Washington DC, thinks that the decrease in spines may have been caused by hormonal changes triggered by the presence of the female, as well as sensory inputs from the penis. These regions may serve as "a one-way road to learn how to mate", he suggests. Once they have been activated for the first time, they may be lost as they are no longer needed. The spines also play a part in the sexual behaviour of female rats. In a separate study, Paul Micevych and his colleagues at the University of California, Los Angeles, investigated the effect on the brain of the female rat's sexual cycle - characterised by an increase in oestradiol production every four days. To control the cycle, the team removed the rats' ovaries and injected them with oestradiol. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory, Learning, and Development
Link ID: 16140 - Posted: 12.13.2011

By Jennifer Welsh Many explanations for the gender gap in math skills don't hold up, suggests new research on math skills and gender in 86 countries. Math has traditionally been seen as a man's game, and the statistics often indicate that there are differences between males and females in their math skills, participation in math activities and performance on tests — called the gender gap in math. Some researchers have proposed this gap is natural — that men are just better at math than women — while others say it's a cultural difference, whereby society somehow keeps girls from pursuing or excelling in math. The new research points to culture as the culprit, finding that certain countries showed less of a gap between males and females in math. Specifically, these female-math friendly countries have more gender equality, better teachers and fewer students living in poverty. In many countries, there isn't a gender gap in mathematics performance, the researchers said. As for the United States, they say the gap has greatly narrowed in recent decades as more females are considered "highly gifted mathematicians" (3 to 1 now, instead of 13 to 1 in the 1970s) and more women are getting graduate degrees in math, though 70 percent are still men. "This is not a matter of biology: None of our findings suggest that an innate biological difference between the sexes is the primary reason for a gender gap in math performance," study researcher Janet Mertz, of the University of Wisconsin-Madison, said in a statement. The study suggests that "the math-gender gap, where it occurs, is due to sociocultural factors that differ among countries, and that these factors can be changed." © 2011 LiveScience.com.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16139 - Posted: 12.13.2011

By Bella English Jonas and Wyatt Maines were born identical twins, but from the start each had a distinct personality. Jonas was all boy. He loved Spiderman, action figures, pirates, and swords. Wyatt favored pink tutus and beads. At 4, he insisted on a Barbie birthday cake and had a thing for mermaids. On Halloween, Jonas was Buzz Lightyear. Wyatt wanted to be a princess; his mother compromised on a prince costume. Once, when Wyatt appeared in a sequin shirt and his mother’s heels, his father said: “You don’t want to wear that.’’ “Yes, I do,’’ Wyatt replied. “Dad, you might as well face it,’’ Wayne recalls Jonas saying. “You have a son and a daughter.’’ That early declaration marked, as much as any one moment could, the beginning of a journey that few have taken, one the Maineses themselves couldn’t have imagined until it was theirs. The process of remaking a family of identical twin boys into a family with one boy and one girl has been heartbreaking and harrowing and, in the end, inspiring — a lesson in the courage of a child, a child who led them, and in the transformational power of love. Wayne and Kelly Maines have struggled to know whether they are doing the right things for their children, especially for Wyatt, who now goes by the name Nicole. Was he merely expressing a softer side of his personality, or was he really what he kept saying: a girl in a boy’s body? Was he exhibiting early signs that he might be gay? Was it even possible, at such a young age, to determine what exactly was going on? © 2011 The New York Times Company

Related chapters from BP6e: 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: 16138 - Posted: 12.13.2011

By PAMELA PAUL IF you believe men think about sex all day long, you’re wrong. According to a study to be published in the January issue of The Journal of Sex Research, the statistic oft-cited by the sex-obsessed or those critical of the sex-obsessed — that men think about sex every seven seconds — is way off. “The story about this paper that’s been reported in the press has been ‘Men think about sex 19 times a day!’ ” said Terri Fisher, a psychology professor at Ohio State University at Mansfield, and the study’s lead author. But that isn’t all that much when you consider the study’s participants were college students, those repositories of raging hormones and unfettered urges. “The more interesting finding is that male college students think just as much about food and sleep as they do about sex,” Dr. Fisher said. To determine how much time people devoted to such thoughts, the researchers asked 283 students age 18 to 25 to use clickers (golf score counters), whenever they contemplated one of life’s three basic needs. Previous studies on the subject were overwhelming retroactively self-reported; researchers asked people after the fact to recollect how often they thought about sex, a method fraught with error. Of course, all kinds of caveats still apply. Did they worry about clicking too often, or too infrequently, and self-adjust accordingly? What kind of thoughts were they having? Was it, “I’d really like to sleep with my boss’s new assistant” or “I wonder whether squirrels mate in the spring?” © 2011 The New York Times Company

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 14: Attention and Consciousness
Link ID: 16128 - Posted: 12.10.2011

By Jonah Lehrer Email Author The human mind sees minds everywhere. Show us a collection of bouncing balls and we hallucinate agency; a glance at a stuffed animal and we endow it with a mood; I’m convinced Siri doesn’t like me. The point is that we are constantly translating our visual perceptions into a theory of mind, as we attempt to imagine the internal states of teddy bears, microchips and perfect strangers. Most of the time, this approach works well enough. If I notice someone squinting their eyes and clenching their jaw, I automatically conclude that he must be angry; if she flexes the zygomatic major – that’s what happens during a smile – then I assume she’s happy. The point is that a few cues of body language are instantly translated into a rich mental image. We can’t help but think about what other people are thinking about. But this intricate connection between mind theorizing and sensory perception can also prove problematic. For instance, when people glance at strangers who look “different” – perhaps they dress funny, or belong to a different ethic group – they endow these strangers with less agency, a fancy term for the ability to plan, act and exert self-control. Or consider a 2010 fMRI experiment that found that when men glance at “sexualized” women they exhibit reduced activation in parts of the brain typically associated with the attribution of mental states. These are obviously terrible habits – a hint of cleavage shouldn’t make us care less about someone’s feelings, nor should a different skin tone – but we mostly can’t help it. We judge books by the cover and minds by their appearance. We are a superficial species. © 2010 Condé Nast Digital.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16127 - Posted: 12.10.2011

by Michael Marshall If you believe European folklore, malevolent fairies are lurking outside family homes. Each one hopes to steal a baby and leave her own child in their place: a changeling. If you are a songbird, there is some truth to the story. Cuckoos dump their eggs in the nests of other species, often killing the rightful offspring. Such brood parasites can get pretty savage themselves: greater honeyguide chicks kill their hosts' offspringMovie Camera. Not always, though. The shiny cowbird does kill some of the host's chicks, but not all of them – and sometimes having a cowbird egg lurking in your nest can even be a good idea. As a group, cowbirds get their name because they follow herds of hoofed mammals such as buffalo, feeding on insects kicked up by the animals' hoofs. This may explain why they lay their eggs in other birds' nests: they can't stay in the same place long enough to raise their own young. Shiny cowbirds aren't fussy about who they exploit. Their eggs have been found in the nests of more than 250 species, although they do tend to go for hosts larger than themselves, and individual females can be fairly consistent. Perhaps because they use so many different hosts, cowbird eggs come in a range of colours and patterns. The female lays her eggs around the same time as the host, so that all the eggs in the nest hatch together. She does so when the parents are out foraging – although they sometimes catch her in the act and attack her. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: 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: 16120 - Posted: 12.08.2011

A new report shows that female Grade 8 students are outperforming their male counterparts in Canada on reading and science, with no discernable difference between the two genders in math skills. The report, released Monday, outlines the results of the 2010 Pan-Canadian Assessment Program (PCAP) from the Council of Ministers of Education in Canada. It's based on test results from 32,000 Grade 8 students from more than 1,600 schools across the country, providing a national report card. Girls scored better than boys in both science and reading, lending credence to the view that boys need a push in several subjects. Break-down by province Students in Quebec and Ontario scored above the national average on math. They scored near the national average in Alberta, and below the average in all other provinces and territories tested. When it comes to science, students in Alberta and Ontario scored above the national average. They scored near the national average in British Columbia and Prince Edward Island, and below the average in all other provinces and territories tested. On the reading portion, students in Ontario and Alberta scored above the national average. They scored near the national average in British Columbia, and below the average in all other provinces and territories tested. © CBC 2011

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16086 - Posted: 11.29.2011

Sandrine Ceurstemont, New Scientist TV The mysterious origin of the female orgasm hasn't yet been solved, but now the world's first movie of the brain during sexual climax maps activity before, during and after the event. Created by animators from theVisualMD, it's based on brain scans captured by Barry Komisaruk of Rutgers University, New Jersey, and his team as a woman stimulated herself inside an fMRI machine. The animation uses a colour scale that varies from red to white, where yellow and white are linked to highest levels of activity. The first sequence uses snapshots of 20 moments during the 7-minute scan. Initially, genital touching fires up a region of the sensory cortex but signals quickly spread to the limbic system, an area linked to emotion, behaviour and long-term memory. Then the cerebellum and frontal cortex light up as muscles become tense before climax. During orgasm, almost the whole brain becomes highly active, as demonstrated by the bright yellow colours. This stage is highlighted in the second part of the animation. Activity then returns to lower levels. Komisaruk hopes that this map of the brain will help explain conditions where women have difficulty achieving orgasm, by showing where the process breaks down. He's also developing a technique where people can watch their brain activity while inside an fMRI scanner, allowing them to learn how to change brain patterns. This could help treat a range of conditions such as pain, anxiety and depression. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: 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: 16054 - Posted: 11.19.2011

By Susan Milius Small rodents called voles have their own battles of the sexes over macho traits. And it turns out that dominant voles don’t always come out on top, which may explain one way a species maintains genetic diversity. Among European rodents called bank voles (Myodes glareolus), dominant males readily trounce meeker ones in disputes over rights to court females, explains Mikael Mokkonen of the University of Jyväskylä in Finland. But the genetic mix underlying these supercharged males doesn’t work well when females inherit it. Sisters of the truculent top voles tend to have small litters of pups, he and his colleagues confirm in the Nov. 18 Science. “You can think of sexual conflict as a tug-of-war over a trait value because what’s optimal for males is not optimal for females,” Mokkonen says. Researchers have proposed that the evolutionary push and pull of such conflicts — favoring a dominant genetic mix at times in males but disfavoring it in females — keeps variety in a population. That possibility has become a hot topic in recent years as one possible solution for a central puzzle in biology: “If selection strongly favors some gene or some trait, why do we see so much variation in natural populations?” says evolutionary biologist Robert Cox of the University of Virginia, who studies male-female issues in lizards. For bank voles, sexual conflict by itself isn’t enough to preserve variations indefinitely, Mokkonen and his colleagues conclude. Warring sides probably aren’t perfectly balanced, and the researchers’ computer simulations found that genetic variation dwindles over the course of generations. © Society for Science & the Public 2000 - 2011

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 16050 - Posted: 11.19.2011

By PAULINE W. CHEN, M.D. The middle-aged patient with long dark hair made it very clear that this was not her first urinary tract infection. “It’s because when I urinate,” she said, “I need to use a catheter.” She opened the leather satchel on her lap and, to prove her point, pulled out a thin, red sterile length of tube covered in plastic. “Just ask one of the older nurses or doctors,” she said, smiling. “They all know me.” But as I would learn, it was not because of her recurrent infections that so many of my colleagues knew her. Several years earlier, she had come in for a routine operation. The doctor had evaluated her before the operation, learned that she was a homemaker and met her husband. But on the morning of her operation, as he pulled down the sheets to begin inserting the urinary catheter into his now sleeping patient, he was startled to discover that the patient was not exactly who he had assumed she was. She was transgender, and where he had been expecting to find female genitalia, he found male genitals instead. The operation had gone well; but years later the doctor’s glaring oversight continued to haunt the rest of us. The patient had obviously not felt comfortable disclosing her transgender identify, and the doctor had clearly not asked the right questions. We knew that any one of us could have made the same mistake. While we had been trained well in treating cancer with the best chemotherapy regimen, curing flesh-eating infections with the most powerful antibiotics or transplanting organs with the greatest of ease, when it came to caring for patients who were transgender, we were lost. For many of us, the same could be said for lesbian, gay and bisexual patients as well. The only thing most of us knew how to do was ask about a single issue: “Whom are you having sex with? Men, women or both?” © 2011 The New York Times Company

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16018 - Posted: 11.11.2011

by Michael Marshall Gliding over a bed of reeds in south-west France, a male western marsh harrier circles his nest. Scanning the surrounding area, he spots a second male on a nest just 400 metres away from his own. Ordinarily this would be the start of a fight. Male marsh harriers are territorial, and don't like another male to set up home within 700 metres of the nest. Yet the new neighbour merits nothing more than a long look. That's because the interloper is a cross-dresser. Ever since he reached sexual maturity, his feathers have been coloured like a female's. Marsh harriers are one of only two bird species – and the only bird of prey – where some of the males mimic females. Male marsh harriers are mostly grey, with yellow eyes, while females are brown with white heads and shoulders, and brown eyes. Females are also about 30 per cent bigger than males. Not all males obey the gender rules, though. Up to 40 per cent of them have mainly brown feathers with no greys at all, though they do still have the yellow eyes that mark them as male, and are no bigger than expected for their gender. These female-like males acquire their unusual colour in their second year, and keep it for the rest of their lives. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16000 - Posted: 11.08.2011

By Dina ElBoghdady, A chemical used widely in plastic bottles, metal cans and other consumer products could be linked to behavioral and emotional problems in toddler girls, according to a government-funded study published online Monday in the journal Pediatrics. After tracking 244 Cincinnati-area mothers and their 3-year-olds, the study concluded that mothers with high levels of bisphenol A (BPA) in their urine were more likely to report that their children were hyperactive, aggressive, anxious, depressed and less in control of their emotions than mothers with low levels of the chemical. While several studies have linked BPA to behavioral problems in children, this report is the first to suggest that a young girl’s emotional well-being is linked to her mother’s exposure during pregnancy rather than the child’s exposure after birth. Girls were more sensitive to the chemical in the womb than boys, maybe because BPA mimics the female hormone estrogen, which is thought to play a role in behavioral development. The results add to a growing body of research that suggests exposure to BPA poses health risks in humans. While the federal government has long maintained that low doses of BPA are safe, the Food and Drug Administration and other federal agencies are taking a closer look and investing in more research about the chemical’s health effects. © 1996-2011 The Washington Post

Related chapters from BP6e: 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: 15959 - Posted: 10.29.2011

By Jesse Bering There are signs, some would say omens, glimmering in certain children’s demeanors that, probably ever since there were children, have caused parents’ brows to crinkle with worry, precipitated forced conversations with nosy mothers-in-law, strained marriages and ushered untold numbers into the deep covenant of sexual denial. We all know the stereotypes: an unusually light, delicate, effeminate air in a little boy’s step, often coupled with solitary bookishness, or a limp wrist, an interest in dolls, makeup, princesses, dresses and a staunch distaste for rough play with other boys; in little girls, there is the outwardly boyish stance, perhaps a penchant for tools, a lumbering gait, a square-jawed readiness for physical tussles with boys, an aversion to all the perfumed, delicate, laced trappings of femininity. So let’s get down to brass tacks. It’s what these behaviors signal to parents about their child’s incipient sexuality that makes them so undesirable—these behavioral patterns are feared, loathed and often spoken of directly as harbingers of adult homosexuality. However, it is only relatively recently that developmental scientists have conducted controlled studies with one clear aim in mind, which is to go beyond mere stereotypes and accurately identity the most reliable signs of later homosexuality. In looking carefully at the childhoods of now-gay adults, researchers are finding an intriguing set of early behavioral indicators that homosexuals seem to have in common. And, curiously enough, the age-old homophobic fears of parents seem to have some genuine predictive currency. © 2011 Scientific American,

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 15939 - Posted: 10.24.2011

by Michael Marshall Supposedly, if women live together their hormonal cycles start to synchronise, thanks to a pheromone. If that were true it would mean that they all have their period simultaneously. Just think about it. This "menstrual synchrony" argument was first reported in 1971 by psychologist Martha McClintock, who noticed signs of it in her own college dorm. But it may not really exist. Studies have had mixed results, often reporting no synchrony at all. Assamese macaques, however, have evolved an unmistakable kind of synchrony: they all have sex at the same time. Assamese macaques live in troupes of a few dozen, including about a dozen adults of each sex, plus offspring. Although there are strong social bonds within the troupes, they are dominated by the males, who compete vigorously to mate with the females. The mating season runs from October to January, and the males become increasingly aggressive as it goes on. The males do show some solidarity. If a female attacks a male, other males will rally to his defence. But it is the females who form close friendships with each other, while males are only loosely allied with their fellows. The females also have ways of resisting the males' control of the troupes, says Ines Fürtbauer of the University of Göttingen in Germany. For one thing, like human females, they do not show external signs of fertility, so males have no way of knowing whether the female they are mating with is actually able to conceive. The females mate throughout their cycles, further confusing the issue. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 15929 - Posted: 10.22.2011