By Victoria Gill Science reporter, BBC Nature, Ottawa, Canada Male fireflies, known for attracting mates with a flash of light, also seduce with a gift, say scientists. This gifts comes in the form of a spermatophore: a package containing sperm and nourishment for the female. Researchers from Tufts University in Boston, US, found that females preferred males that had the largest, most nourishing gift. The team presented their findings at the First Joint Congress on Evolutionary Biology in Ottawa, Canada. With supervision from his colleague Sara Lewis, who has been studying fireflies for 20 years, Dr Adam South used LED lights to mimic the flashes of amorous male fireflies. They showed one group of females artificial male flashes in patterns and durations that had been proven attractive in previous studies. Another group of females saw "unattractive" flashes. In the wild, females are very picky about what males they reveal themselves to during this part of the courtship routine. Females will only "flash back" to males they are attracted to. But in this experimental set-up, after several minutes of the courtship flashing, males and females were paired together in miniature chambers. The Tufts biologists filmed the encounters under infrared illumination to see what was happening when the lights went out. 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: 17013 - Posted: 07.09.2012

By Jesse Bering We all know the stereotypes: an unusually light, delicate, effeminate air in a little boy's step, an interest in dolls, makeup, princesses and dresses, and a strong distaste for rough play with other boys. In little girls, there is the outwardly boyish stance, perhaps a penchant for tools, a square-jawed readiness for physical tussles with boys, and an aversion to all the perfumed, delicate trappings of femininity. These behavioral patterns are feared, loathed and often spoken of directly as harbingers of adult homosexuality. It is only relatively recently, however, that developmental scientists have conducted controlled studies to identify the earliest and most reliable signs of adult homosexuality. In looking carefully at the childhoods of gay adults, researchers are finding an intriguing set of behavioral indicators that homosexuals seem to have in common. Curiously enough, the age-old homophobic fears of many parents reflect some genuine predictive currency. J. Michael Bailey and Kenneth J. Zucker, both psychologists, published a seminal paper on childhood markers of homosexuality in 1995. Bailey and Zucker examined sex-typed behavior—that long, now scientifically canonical list of innate sex differences in the behaviors of young males versus young females. In innumerable studies, scientists have documented that these sex differences are largely impervious to learning. They are also found in every culture examined. Of course, there are exceptions to the rule; it is only when comparing the aggregate data that sex differences leap into the stratosphere of statistical significance. © 2012 Scientific American

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: 17008 - Posted: 07.07.2012

by Michael Slezak Evolutionary biologists have a problem with sex in difficult places. Earth's complex and varied environments should, in theory, offer asexual species advantages over their sexual counterparts, says Matthew Goddard at the University of Auckland in New Zealand. An asexual species should adapt more quickly to a specific niche in the environment than a sexual species, because gene mixing between sexual individuals from different niches will produce maladapted hybrids that will not reliably pass on useful adaptations. "All else being equal, the sexual populations should be outcompeted by asexual populations," says Goddard. But the evidence around us suggests that this doesn't actually happen: environmental niches are almost always far more complex than the simple set-ups used in most lab experiments, and yet sexual species abound. To get a clearer idea of what is going on, Goddard and his Auckland colleague, Jeremy Gray, turned to yeast, single-celled organisms that can reproduce sexually or asexually. Goddard and Gray created two environments for the yeast in their lab – one containing relatively little carbon at an uncomfortably hot 37 °C, the other limited for nitrogen instead, at a less stressful 30 °C but with an "osmotic stress" caused by an unusual balance of salts. The researchers then placed sexual and asexual populations in both environments. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 0: ; Chapter 8: Hormones and Sex
Link ID: 17007 - Posted: 07.07.2012

by Michael Marshall The male fish, a Phallostethus cuulong just 2 centimetres long, weaves between drifting vegetation in the sluggish waters of a canal. He closes in on a female, swims alongside her and tries to mate with her. But to an outside observer, he seems to be doing it wrong. His head is right next to the female's, but he's at a 45-degree angle so his rear end is well below hers. Sounds misguided, but actually he's doing it exactly right – it's just that his gonads are on his head. This is the challenge faced by all priapiumfish, a little-known group of Asian fish that have their reproductive organs on their chins, just behind their mouths. How does this Cronenbergian arrangement work? Phallic fish P. cuulong is only the 22nd known priapiumfish, which are named after the ancient Greek fertility deity, Priapus. They all belong to a family called Phallostethidae and live in south-east Asia. The new species was discovered in July 2009 by Koichi Shibukawa of the Nagao Natural Environment Foundation in Tokyo, Japan. He saw one swimming alone in a canal near the Mekong River in Vietnam, and managed to catch it in a net. Working with colleagues at Can Tho University in Vietnam, he realised it was a new species. Male priapiumfish don't have a penis like humans and other mammals. Instead they have a unique organ called a priapium, which faces backwards and looks like a muscular nozzle. It's actually a modification of the fish's pectoral and pelvic fins. © 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: 17006 - Posted: 07.07.2012

by Sarah C. P. Williams Talk about showing your feminine side. On one flank, a courting male cuttlefish looks like a normal male of his species, with tigerlike stripes extending horizontally down his skin. But on the other, he resembles a female, displaying marbled browns and whites. He needs the male pattern to attract the female, while the female motif keeps competing males from fighting him. That’s scientists’ best guess for now, at least, to explain the devious cuttlefish behavior that they’ve observed and reported for the first time. “Cuttlefish are a very smart group of fish,” says lead researcher and ecologist Culum Brown of Macquarie University in Sydney, Australia. “And it’s pretty obvious that they are specifically using this display in a tactical way.” Researchers knew that cuttlefish (Sepia plangon) could camouflage their skin to match their surroundings, and that they could show different patterns on each side. Their skin contains a highly concentrated layer of chromatophores—various colored pigment-containing cells—that can be moved closer or further from the surface to change the pattern on the fish. But scientists had never seen a male fish mimicking a female on only one side as a trick of courtship. Brown and his colleagues first observed the behavior in a large aquarium in their lab. They wondered whether males in the wild did the same thing, and if so, when and why. So they combed through photos of 108 distinct groups of cuttlefish taken on previous dives of Sydney Harbour. They found that when a male was in a group with one female and one other male, he displayed the dual patterns—a male side facing the female and a female side facing the male—39% of the time. In other situations, such as an all-male group or a male matched with two females, the dual display was never seen. © 2010 American Association for the Advancement of Science.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 17004 - Posted: 07.05.2012

By Helen Shen, Globe Correspondent The International Olympic Committee has issued new rules for the 2012 London Games that would require checking testosterone levels in athletes whose eligibility as females is called into question. Several elite female athletes have previously been accused of secretly being males, including South African runner Caster Semenya , who was investigated and later cleared after her 2009 world championship victory in the 800-meter event drew accusations from competitors. The IOC says its intent is to identify athletes who would be ineligible “by reason of hormonal characteristics” -- not to determine gender, but the policy has drawn criticism. Stanford University bioethicist Katrina Karkazis said the inclusion of a gynecologist and geneticist on the IOC examining panel contradicts this message. “It’s way more than a blood test or a series of blood tests. There will be genital exams, there will be genetic testing,” she said. Athletes will be disqualified to compete as females if they are found with testosterone levels typical of males, and if they possess cellular receptors that respond to the hormone’s effects, which include boosting muscle mass and strength. “They chose something that really does discriminate between males and females,” said Dr. Joshua Safer, an endocrinologist at Boston Medical Center and expert in transgender care. Testosterone levels vary from one individual to another and, for a given individual, can vary widely by time of day. But the overall ranges of testosterone are about 10 times higher in men than in women, he said. © 2012 NY Times Co.

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: 16999 - Posted: 07.03.2012

Content provided by Jeanna Bryner, LiveScience Sometimes mind-blowing sex is not cause for celebration, as some individuals experience intense headaches that explode in pain at the moment of orgasm. Until now, only two cases of these sex headaches had been reported in teenagers. Two new cases, 16-year-old boy and an 18-year-old girl, bring the odd, though not life-threatening, phenomenon to light. And doctors are hoping the sex-headache cases will make both other doctors and teens aware of the temporary disorder. "What I wonder about is whether there are many other adolescents out there who are having this problem and aren't telling anyone," said Dr. Amy Gelfand, a neurologist at the University of California, San Francisco School of Medicine. "This is why pediatricians should be aware of this, so an adolescent doesn't have to raise this issue." About 1 percent of Americans have experienced a headache as the result of sex, called a primary sex headache, in their lifetimes; about 50 percent of individuals who have primary sex headaches also get migraine headaches. Even so, their cause remains a mystery. Primary sex headaches come in two varieties — one that gradually builds up in intensity during sex and the other develops explosively at orgasm. © 2012 Discovery Communications, LLC.

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 5: The Sensorimotor System
Link ID: 16993 - Posted: 07.03.2012

By ABBY ELLIN Since Ms. B. entered her mid-40s, she says, sex has been more about smoke and mirrors than thunder and lightning. She is rarely if ever interested enough to initiate it with her partner of 10 years, and she does not reach climax during the act. She wishes it were otherwise. “Sex just isn’t a priority anymore,” said Ms. B., 45, a professor in New York who spoke on the condition that only her last initial be used. “Still, it would be nice not to feel sexually dead.” Ms. B.’s plight is far from unique, and now the marketplace is starting to respond. In the absence of a government-approved female counterpart to men’s potency drugs like Viagra, Cialis and Levitra, many women are turning to over-the-counter products, including lubricants, arousal gels, massage oils, nutritional and herbal supplements, and vibrators. Drugstore chains are now selling these products right next to the bandages and heating pads. K-Y Intense, a female arousal gel that claims to heighten clitoral sensitivity, is sold in Walmart, Walgreen and Rite Aid. Sensuva’s ON, an arousal oil, can be found in 640 GNC stores nationwide. Intimina by LELO, an “intimate lifestyle line” that manufactures personal massagers, apparel and “intimate cosmetics,” is sold at Pharmaca Integrative pharmacies. And Zestra Essential Arousal Oil is now sold in 1,800 Walmarts, up from 880 in 2010. “The average woman in a committed relationship is having sex once a week,” said Rachel Braun Scherl, president of Semprae Laboratories, the manufacturer of Zestra, which recently signed Kris Kardashian Jenner as a spokeswoman. “Our idea is not to get them to have more sex — it’s that if they’re having sex they should enjoy it.” © 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: 16992 - Posted: 07.03.2012

By Scicurious Before I started college, there was a sudden rage amongst my male friends. A rage for one specific thing. Not phones or computers or cars or clothes. Nope. It was for a guitar. Most of the guys I knew, in the year or two before college, suddenly became obsessed with the guitar, picking out melodies, trying to match still changing warbling voices to a hopefully tuned instrument. I couldn’t figure it out. What was up with the guitar obsession?! Some of these people were people who never had displayed a musical bent their entire lives, and here they were, sitting experimentally on the benches outside my school with guitars in hand. Finally, I asked my brother (who also, of course, had taken up the guitar), why every guy seemed to want to play the guitar. Why not the cello or the piano or the trombone or the kazoo? My brother rolled his eyes at my denseness. “For the GIRLS, of course” (And yes, specifically, they ALL wanted to play this song. I would hypothesize that about 80% of the men I know can pick out this song on the guitar. Considering that a substantial portion of the female populace does indeed have brown eyes, I realize the efficiency of this method, but for those of us with non-brown eyes, this song is IRRITATING BEYOND BELIEF. This has been a public service announcement.) © 2012 Scientific American

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: 16937 - Posted: 06.20.2012

by Helen Fields When a male club-winged manakin (Machaeropterus deliciosus) wants to attract a female in the Andean cloud forest, he raises his wings over his back and vibrates a pair of giant feathers to make a "PEEP!" sound (as in video above). A scientist at Cornell University suspected there were odd bones under those strange feathers, so she teamed up with colleagues to do computed-tomography scans of the manakin and some close relatives. Bird bones are hollow, with air pockets that make flight easier. But the club-winged manakin is an oddball. The scans revealed that its humerus, the bone that starts at the shoulder, is solid. The ulna, in the next section of wing, is also solid. It's also just plain wacky: While the other birds' ulnae are long, thin, and smooth with a knob at each end, the club-winged manakin's ulna is shaped like a club and covered with lumps and bumps. (And yet they still manage to fly.) The scientists, who report their findings online today in Biology Letters, think the bumps grasp the ends of the special resonating feathers, which poke through the skin, for better sound control, and that the dense bone may make the sound louder by bouncing it out through the feather. © 2010 American Association for the Advancement of Science

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Language and Our Divided Brain
Link ID: 16906 - Posted: 06.13.2012

The merest interaction with a member of the opposite sex can bring a glow to a woman's face, according to a new study. Researchers at the University of St Andrews found even non-sexual contact with men caused a noticeable rise in the temperature of a woman's face. The team used thermal imaging to detect changes in heterosexual women during their meetings with other people. They found that even without noticing, a woman's face would heat up in the company of the opposite sex. The team behind the discovery said the findings could be used in the development of thermal imaging to monitor levels of stress and emotion in future, for example in lie detection tests. Lead author of the study, Amanda Hahn, said researchers measured skin temperature on a woman's hand, arm, face and chest when they interacted with men. They found the most dramatic increase occurred in a woman's face, where temperatures rose by an entire degree in some cases. She said: "This thermal change was in response to simple social interaction, without any experimental change to emotion or arousal. Indeed our participants did not report feeling embarrassment or discomfort during the interaction." BBC © 2012

Related chapters from BP6e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16890 - Posted: 06.09.2012

Ewen Callaway Trespassers on the mating grounds of male bumphead parrotfish soon learn a hard lesson. The reef-munching fish fend off competing males using aggressive headbutting — a form of behaviour that has never previously been seen in the species. A team of US researchers reveals the surprising finding in the journal PLoS ONE this week1. Growing to a weight of more than 75 kilograms and up to 1.5 metres in length, the giant bumphead parrotfish (Bolbometopon muricatum) is one of the heftiest reef fish in the world — but also one of the most shy around humans. “These really are underwater buffalos, gentle giants that play a critical role in coral reef ecology. But when reproduction is involved, it is time to fight,” says David Bellwood, a marine ecologist at James Cook University in Townsville, Australia, who was not involved in the study. The fish are named for their prominent forehead ridge, which in the males is reinforced by a thick bony plate. Scientists thought that bumpheads used this armour to ram coral reefs and break them up for feeding — but no one had ever seen them do it. With one bumphead eating as much as 5 tonnes of reef in a year, Bellwood and other bumphead experts had their doubts; the bony bit isn’t very large and the fish have powerful jaws for biting the coral anyway. © 2012 Nature Publishing Group,

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: 16889 - Posted: 06.09.2012

by Kayt Sukel The sexes may be more alike than we thought. A startling new theory says that some of the disparities between our brains may be there to make us act the same SEVERAL years ago, the car I was driving was rear-ended by another at a stop sign. No one was hurt, but my passenger and I had to wait around to give a statement to the local police. Later on I asked my companion if he had noticed that the officer addressed most of the questions to him, even though I was the one who had been driving. "I think he was just afraid you were going to do the typical female thing and fall apart," he replied. The notion that men can face adversity with stoicism while women are more likely to respond with histrionics is just one example of the gender stereotypes that permeate our culture. If my friend was right, they even persist among those who should be taking particular care to treat people equally. Perhaps such prejudice is justified, though. After all, in recent years evidence has turned up of numerous differences between men and women's brains, whether at the level of synapses, signalling chemicals, or gross anatomy. Brains come in hues of either pink or blue, as one researcher puts it. But could we be overlooking an important caveat? A new theory that has sprung from research on prairie voles says that at least some of those disparities evolved not to create differences in behaviour or ability, but to prevent them. They are there to compensate for the genetic or hormonal differences that are necessary to create two sexes with different sets of genitals and reproductive behaviours. © 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: 16856 - Posted: 05.31.2012

By BENEDICT CAREY PRINCETON, N.J. — The simple fact was that he had done something wrong, and at the end of a long and revolutionary career it didn’t matter how often he’d been right, how powerful he once was, or what it would mean for his legacy. Dr. Robert L. Spitzer, considered by some to be the father of modern psychiatry, lay awake at 4 o’clock on a recent morning knowing he had to do the one thing that comes least naturally to him. He pushed himself up and staggered into the dark. His desk seemed impossibly far away; Dr. Spitzer, who turns 80 next week, suffers from Parkinson’s disease and has trouble walking, sitting, even holding his head upright. The word he sometimes uses to describe these limitations — pathetic — is the same one that for decades he wielded like an ax to strike down dumb ideas, empty theorizing and junk studies. Now here he was at his computer, ready to recant a study he had done himself, a poorly conceived 2003 investigation that supported the use of so-called reparative therapy to “cure” homosexuality for people strongly motivated to change. What to say? The issue of gay marriage was rocking national politics yet again. The California State Legislature was debating a bill to ban the therapy outright as being dangerous. A magazine writer who had been through the therapy as a teenager recently visited his house, to explain how miserably disorienting the experience was. © 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: 16816 - Posted: 05.19.2012

By Rebecca Cheung Unique wings allow one type of male tree cricket to hum a different sort of tune — one that encompasses a wide range of pitches. The discovery could mean that these males are saying a lot more than previously thought, and that potential mates might be listening for these notes. “The frequencies might be carrying some information about the condition of the male. An insect that is able to sing faster, and hence at a higher frequency, might actually be quite well fed, or he’s in a nice warm place you might want to be in,” says Natasha Mhatre of the University of Bristol in England. “You now have to ask: ‘What kind of information is that frequency carrying?’” Crickets produce sound by rubbing their wings together. For most crickets — including field and bush crickets — males can produce only one musical note. Generally, the pitch of the male’s song is directly related to his size. Researchers believe that when females scout for a potential mate, they tend to be drawn to songs of deeper frequency or pitch, which are produced by larger crickets. But certain tree crickets were known to vary their tune. Scientists had observed, for instance, that a species from southern India called Oecanthus henryi produces high-pitch sounds at warmer temperatures. Until now, it wasn’t fully understood how these critters could do this. © Society for Science & the Public 2000 - 2012

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: 16732 - Posted: 05.01.2012

by Helen Thomson G marks the spot. Or does it? One researcher claims to have pinpointed and described the anatomy of the elusive G spot, an area of the vagina reputed to produce intense orgasms when stimulated. Many others are not so sure, saying that the G spot is unlikely to be a single structure. "It's akin to concluding that the Empire State Building is New York City," says Barry Komisaruk at Rutgers University in Newark, New Jersey. The G spot refers to an area on the front of the vaginal wall, a few centimetres from the entrance of the vagina. Stimulating this area is said to cause swelling and create an orgasm without stimulating the clitoris. As far back as the 11th century, ancient Indian texts described a sensitive area in the vagina inducing sexual pleasure. In 2008, Emmanuele Jannini at the University of L'Aquila in Italy discovered anatomical differences in the thickness of tissue in the region between the vagina and urethra in women who claimed to have vaginal orgasms compared with those who did not. However, a recent review of G spot research published since 1950 concluded that objective measures "have failed to provide strong and consistent evidence for the existence of an anatomical site related to the G spot" (The Journal of Sexual Medicine, DOI: 10.1111/j.1743-6109.2011.02623.x). © 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: 16705 - Posted: 04.25.2012

By DOUGLAS QUENQUA CAMBRIDGE, Mass. — For a table set up by a campus student group, this one held some unusual items: a gynecologist’s speculum, diaphragms, condoms (his and hers) and several packets of lubricant. Nearby, two students batted an inflated condom back and forth like a balloon. “This is Implanon,” said Gabby Bryant, a 22-year-old senior who had helped set up the table, showing off a sample of the implantable birth control. “Here at Harvard, you get it for free.” It was Sex Week at Harvard, a student-run program of lectures, panel discussions and blush-inducing conversations about all things sexual. The event was Harvard’s first, though the tradition started at Yale in 2002 and has since spread to colleges around the country: Brown, Northeastern, the University of Kentucky, Indiana University and Washington University have all held some version of Sex Week in recent years. Despite the busy national debate over contraception and financing for reproductive health, Sex Week at Harvard (and elsewhere) has veered away from politics, emerging instead as a response to concern among students that classroom lessons in sexuality — whether in junior high school or beyond — fall short of preparing them for the experience itself. Organizers of these events say that college students today face a confusing reality: At a time when sexuality is more baldly and blatantly on display, young people are, paradoxically, having less sex than in generations past, surveys indicate. © 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: 16666 - Posted: 04.17.2012

By Jeanna Bryner and LiveScience Homophobes should consider a little self-reflection, suggests a new study finding those individuals who are most hostile toward gays and hold strong anti-gay views may themselves have same-sex desires, albeit undercover ones. The prejudice of homophobia may also stem from authoritarian parents, particularly those with homophobic views as well, the researchers added. "This study shows that if you are feeling that kind of visceral reaction to an out-group, ask yourself, 'Why?'" co-author Richard Ryan, a professor of psychology at the University of Rochester, said in a statement. "Those intense emotions should serve as a call to self-reflection." The research, published in the April 2012 issue of the Journal of Personality and Social Psychology, reveals the nuances of prejudices like homophobia, which can ultimately have dire consequences. [The 10 Most Destructive Human Behaviors] "Sometimes people are threatened by gays and lesbians because they are fearing their own impulses, in a sense they 'doth protest too much,'" Ryan told LiveScience. "In addition, it appears that sometimes those who would oppress others have been oppressed themselves, and we can have some compassion for them too, they may be unaccepting of others because they cannot be accepting of themselves." Ryan cautioned, however, that this link is only one source of anti-gay sentiments. © 2012 Scientific American,

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: 16636 - Posted: 04.12.2012

Roger Dobson It is the chemical that has been described by women as a "cuddle drug". Now scientists have discovered that its effect on men is more rampant and long-lasting than just the desire for a quick hug. Oxytocin, a hormone traditionally used to induce labour, is as sexually arousing to men as Viagra, according to new research. Studies conducted in the US found that a married man who sniffed a nasal spray containing oxytocin twice daily became more affectionate to friends and colleagues and recorded a marked improvement in his sexual performance. According to the actual breakdown of results, the man's libido went from "weak to strong", while arousal went from "difficult to easy". Ego certainly wasn't hurt either: sexual performance, according to feedback from his wife, was classed as "very satisfying". Scientists at the University of California believe the findings provide strong support for the idea that oxytocin improves sexual performance and, unlike Viagra, remains a chemical glue within the brain to cement relationships between people. Just how it works is not clear, but some studies have suggested that oxytocin levels rise naturally during arousal. The hormone is also thought to interact with the dopamine system, which is involved in the rewarding aspects of sexual activity. © independent.co.uk

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: 16623 - Posted: 04.09.2012

by Michael Marshall One of the most important things any animal can do is to tell potential mates about themselves. They have all sorts of ways to do it, from peacocks' ridiculously large and ornamented tails to the sharp suits and gym-honed bodies of posing human males. If it weren't a matter of life and death, it would all seem very, very silly. Many of these signals come in the form of secondary sexual characteristics: parts of the body that aren't directly involved in producing offspring, but are nevertheless associated with the process. The peacock's train is one example; in humans, male body hair is a signal of reproductive maturity, and large female breasts are renowned for attracting male attention. But female red-spotted newts may need to look a little more closely when they choose their mates. Specifically, if they want a good one, they would be well-advised to take a look at his kidneys. The same may be true of many salamanders. Kidneys before sex Red-spotted newts have a peculiar way of mating. In common with many other salamanders, the male produces a blob of jelly called a spermatophore, which carries a consignment of sperm. The female stores it until she is ready to reproduce. But according to Dustin Siegel of Southeast Missouri State University in Cape Girardeau, before all this happens, the male's kidneys have to do their bit. © 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: 16620 - Posted: 04.07.2012