Links for Keyword: Sexual Behavior

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By C. CLAIBORNE RAY Q. Are men more likely to be claustrophobic than women? A. The opposite seems to be true, as is the case in almost all anxiety disorders, large epidemiological studies have found. The reasons for such a gender difference are not clear, and claustrophobia, the feeling of extreme panic when faced with being in a confined or enclosed space, is not as well studied as some other phobias. One situation that has been comparatively well researched is what happens when people need magnetic resonance imaging, which often involves a prolonged period of confinement in a small enclosure, the perfect storm of claustrophobia triggers. A recent study found that certain factors seem to correlate with an increase in claustrophobic reactions, including being female, going into the scanner head first and having a previous negative experience with the test. Another large study involving scanners with a shorter chamber and noise reduction found a significant reduction in claustrophobic reactions, but being female and middle-aged were still associated with a higher rate of claustrophobia. It has often been assumed that claustrophobia develops as a response to a traumatic experience, like being trapped in a closet as a child, but newer research suggests a genetic component. In one study in mice, a single defective gene was associated with claustrophobia. question@nytimes.com © 2015 The New York Times Company

Related chapters from BP7e: 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: Biological Basis of Behavioral Disorders
Link ID: 21230 - Posted: 07.29.2015

Qazi Rahman In a recent Guardian article , Simon Copland argued that it is very unlikely people are born gay (or presumably any other sexual orientation). Scientific evidence says otherwise. It points strongly to a biological origin for our sexualities. Finding evidence for a biological basis should not scare us or undermine gay, lesbian and bisexual (LGB) rights (the studies I refer to do not include transgendered individuals, so I’ll confine my comments to lesbian, gay and bisexual people). I would argue that understanding our fundamental biological nature should make us more vigorous in promoting LGB rights. Let’s get some facts and perspective on the issue. Evidence from independent research groups who studied twins shows that genetic factors explain about 25-30% of the differences between people in sexual orientation (heterosexual, gay, lesbian, and bisexual). Twin studies are a first look into the genetics of a trait and tell us that there are such things as “genes for sexual orientation” (I hate the phrase “gay gene”). Three gene finding studies showed that gay brothers share genetic markers on the X chromosome; the most recent study also found shared markers on chromosome 8. This latest research overcomes the problems of three prior studies which did not find the same results. Gene finding efforts have issues, as Copland argues, but these are technical and not catastrophic errors in the science. For example, complex psychological traits have many causal genes (not simply “a gay gene”). But each of these genes has a small effect on the trait so do not reach traditional levels of statistical significance. In other words, lots of genes which do influence sexual orientation may fall under the radar. But scientific techniques will eventually catch up. In fact there are more pressing problems that I would like to see addressed, such as the inadequate research on female sexuality. Perhaps this is due to the stereotype that female sexuality is “too complex” or that lesbians are rarer than gay men. © 2015 Guardian News and Media Limited

Related chapters from BP7e: 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: 21219 - Posted: 07.25.2015

THERE’S more to semen than sperm. In many animals, seminal fluid alters both the bodies and sometimes even the behaviour of females. Human semen, too, triggers changes in the uterus, and might have wider effects on women, aimed at just one goal. “It’s all about maximising the chances of the male reproducing,” says Sarah Robertson of the University of Adelaide in Australia. The effects are most striking in fruit flies: seminal fluid can make the females eat more, lay more eggs and be less receptive to other males. Now a team led by Tracey Chapman at the University of East Anglia in Norwich, UK, has found that male fruit flies selectively alter the chemical make-up of their seminal fluid. In the presence of rivals, the males produce more seminal proteins. “It came as a real surprise,” says Chapman. “It’s a sophisticated response to the social and sexual situation.” Some of their findings were presented at the Society for Molecular Biology and Evolution conference in Vienna, Austria, last week, including their discovery that one of these proteins is a “master regulator” of genes. Females exposed to it show a wide range of changes in gene expression. Chapman thinks this kind of seminal signalling is widespread in the animal world. The semen of people, pigs and mice affects the female reproductive tract, and the question is whether it can also produce behavioural responses in female mammals similar to those seen in fruit flies. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: 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: 21209 - Posted: 07.23.2015

by Stephen Buchmann Flowers, bugs and bees: Stephen Buchmann wanted to study them all when he was a kid. "I never grew out of my bug-and-dinosaur phase," he tells NPR's Arun Rath. "You know, since about the third grade, I decided I wanted to chase insects, especially bees." These days, he's living that dream. As a pollination ecologist, he's now taking a particular interest in how flowers attract insects. In his new book, The Reason for Flowers, he looks at more than just the biology of flowers — he dives into the ways they've laid down roots in human history and culture, too. On the real 'reason for flowers' The reason for flowers is actually one word: sex. So, flowers are literally living scented billboards that are advertising for sexual favors, whether those are from bees, flies, beetles, butterflies or us, because quite frankly most of the flowers in the world have gotten us to do their bidding. But that's only the first stage because flowers, if they're lucky, turn into fruits, and those fruits and seeds feed the world. On the raucous secret lives of beetles One of my favorite memories is roaming the Napa foothills as a UC Davis grad student. And I would go to the wineries, of course, and in between I would find western spice bush, which is this marvelous flower that kind of smells like a blend between a cabernet and rotten fruit. And when you find those flowers and open them up, you discover literally dozens of beetles in there, mating, defecating, pollinating — having a grand time. © 2015 NPR

Related chapters from BP7e: 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: 21192 - Posted: 07.20.2015

By THE EDITORIAL BOARD Scientific research has a gender gap, and not just among humans. In many disciplines, the animals used to study diseases and drugs are overwhelmingly male, which may significantly reduce the reliability of research and lead to drugs that won’t work in half the population. A new study published in the journal Nature Neuroscience suggests that research done on male animals may not hold up for women. Its authors reported that hypersensitivity to pain works differently in male and female mice. For males, immune cells called microglia appear to be required for pain hypersensitivity, and inhibiting their function also relieves the pain. But in female mice, different cells are involved, and targeting the microglia has no effect. If these differences occur in mice, they may occur in humans too. This means a pain drug targeting microglia might appear to work in male mice, but wouldn’t work on women. Failure to consider gender in research is very much the norm. According to one analysis of scientific studies that were published in 2009, male animals outnumbered females 5.5 to 1 in neuroscience, 5 to 1 in pharmacology, and 3.7 to 1 in physiology. Only 45 percent of animal studies involving depression or anxiety and only 38 percent involving strokes used females, even though these conditions are more common in women. In 1994, the National Institutes of Health confronted gender imbalance in clinical drug trials and began requiring that women and minorities be included in clinical studies; women now make up around half of clinical trial participants. In June, the N.I.H. announced that it would begin requiring researchers to take gender into account in preclinical research on animals as well. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21188 - Posted: 07.20.2015

Simon Copland Over the past decade the idea that we are “born this way” — or that our sexuality is genetic — has become increasingly important. The mantra has become a political strategy, in particular for gay and lesbian communities, who see it as a way to protect themselves from discrimination. The movement has spawned blogs where people show pictures of their childhood to highlight the innate nature of their sexuality, and attacks on those who have questioned the theory. But do the politics match the science? People have been searching for biological explanations for sexual desires for centuries — primarily as a way to try and find a “cure” for “perverted desires”. In the most horrible of examples, the Nazi regime in Germany invested significant resources in attempts to find the reasons for homosexuality in attempt to cure it. In recent decades the search for a “gay gene” has intensified. In 1991, for example, Simon LeVay released a study that suggested small differences in the size of certain cells in the brain could influence sexual orientation in men. In 1993 this research turned to genetics, when Dean Hamer claimed that markers on the X chromosome could influence the development of same-sex orientation in men. The issue hit the headlines again last year after the release of a study from Dr. Alan Sanders. Sanders studied the genes on 409 pairs of gay brothers, finding they may share genetic markers on the X chromosome and chromosome 8. © 2015 Guardian News and Media Limited

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21154 - Posted: 07.11.2015

By David Shultz Like many arthropods, spiders don’t have penises. Instead they rely on a set of modified appendages—termed pedipalps—to transfer sperm during reproduction. Previous studies had concluded that the pedipalps, which are basically modified arms emanating from the arachnid’s head, were lacking any sort of neurons that might convey a sense of touch. But new research, published online today in Biology Letters, suggests that the spider’s sex life isn’t an entirely numb deal. Using a combination of histological and computer-based techniques, scientists have identified neurons in the pedipalps of the Tasmanian cave spider (Hickmania troglodytes, seen above). Two main groups of nervous tissue were present: a nerve running to the tip of the sex organ, and two clusters of neurons in the palpal bulb—the region of the pedipalps used for transferring sperm. Though further research is needed to confirm the hypothesis, the team suspects that the sense of touch may enable the males to stimulate the females and even provide feedback about the quality of their mate. The latter hypothesis is especially intriguing because the analyses also revealed that one of the glands in the spider’s sex organ was directly innervated. The team believes this might mean the spiders can control the quality and volume of their ejaculate—reserving the best secretions for the choicest mates. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21145 - Posted: 07.08.2015

By Sabrina Imbler To our knowledge, there’s no correlation between a man’s singing ability and his care and attentiveness as a father. But any Pavarotti among the nightingales will serenade his mate while she sits on her eggs. And after they hatch he will visit the nest about 16 times each hour to feed their offspring. Because, among nightingales at least, the best singers also make the best fathers. So finds a study in the journal BMC Evolutionary Biology. [Conny Bartsch, Michael Weiss and Silke Kipper, Multiple song features are related to paternal effort in common nightingales] Some 80 percent of birds practice biparental care, meaning both the male and female rear their offspring together. So it’s crucial for a female bird to pick as a mate the most promising father—both genetically and behaviorally. Female birds look for signs of fitness that range from the flamboyant plumage of the peacock to the bizarre dances of birds of paradise. And for nightingales, it’s the most elaborate song that apparently wins the day. The average male has some 180 tunes in his repertoire. These avian Sinatras vocalize highly variable song types including buzzes, whistles and trills. And such virtuoso singing seems to signal the female that this is a guy she can count on. That is, when it’s time to help raise the kids, he’s not a flight risk. © 2015 Scientific American

Related chapters from BP7e: 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: 21140 - Posted: 07.07.2015

Taunya English What do we know about the power of food to rev up sex drive? Not much. "Really, science has not figured out what determines sexual motivation and sexual attraction. If we knew the answer to that, we'd probably be richer than Pfizer after they invented Viagra," says Dolores Lamb, director of the Center for Reproductive Medicine at Baylor College of Medicine. She hasn't seen any compelling evidence that any particular food can intensify desire. Lamb is a men's health researcher and knows a lot about the intricacies of male plumbing, but she says desire is largely psychological. Even medicines that treat erectile dysfunction can't create enthusiasm. "So the trigger still has to be up in the brain," Lamb says. Still, the idea persists that ginger stirs up lust, or that hot peppers make you hot. "Probably for some folks they do, and it's certainly fun to try," Lamb says. Some legendary aphrodisiacs do have a chemical here or a nutrient there that might support sexual health, but not enough of it to make an immediate difference in the bedroom. Red, juicy watermelon, for example, contains the amino acid citrulline, and that plant nutrient is healthy for erectile tissue in both men and women. But most of the amino acid is found in the rind of the fruit. Consider chili peppers. Capsaicin, which is what provides the heat in a jalapeno, also raises your metabolism and releases feel-good endorphins. "You get kind of a chill down the back of your neck and kind of a tingly, good sensation," Lamb says. "Gets blood flowing better." © 2015 NPR

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21134 - Posted: 07.06.2015

by Michael Le Page It's good to be mixed-up. People whose parents are distantly related are, on average, taller, smarter and better educated than those whose parents are close relatives. Based on what we know about plants and animals, biologists have long suspected that people of mixed parentage have a genetic advantage. Now an extensive study may have confirmed the hunch. "It does imply that people who come from very different ancestry would be a bit taller and a bit more cognitively able," says team member Jim Wilson of the University of Edinburgh, UK. It has long been known that children are more likely to suffer from genetic diseases if their parents are close relatives, because they may inherit the same harmful gene variants from their mother and father. To probe the wider implications, Wilson and his colleagues analysed genome and life history data from 110 genome studies involving 350,000 people from Africa, Asia, Europe and North America. They were surprised to find no evidence of a link between having closely related parents and most of the traits they looked at, such as cholesterol levels, blood pressure and rates of diabetes. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21120 - Posted: 07.02.2015

by Lisa Grossman Marriage for all, no gay gene required. For same-sex couples in the US, 26 June was a landmark date: the Supreme Court legalised marriage between two men or two women in all 50 states. "[Same-sex couples] ask for equal dignity in the eyes of the law," wrote Associate Justice Anthony Kennedy in the decision. "The Constitution grants them that right." But one thing the decision didn't do was declare sexual orientation a "suspect class" under the law, which would have given it the same protection as race. One of the criteria for this classification is that the trait must be immutable – an argument that the gay rights movement has internalised under the banner of "we're born this way". But although there is some evidence that sexual orientation has a genetic component, most scientists agree that it's not that simple. "There's significant consensus in the scientific community that there's enough different interacting causes for sexual orientation that two different individuals can be gay for different combinations of reasons," says sexuality researcher Lisa Diamond at the University of Utah. "I think all the evidence suggests that we're born with an underlying capacity and then that capacity interacts with a whole bunch of other influences," she says – whether they be prenatal, genetic or environmental. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21117 - Posted: 07.01.2015

by Colin Barras Men often lose their sex drive with age – and so, it seems do male Drosophila. Tsai-Feng Fu at the National Chi Nan University in Taiwan and his colleagues suspected that low levels of dopamine in the flies were to blame. Almost 300 neurones in the fruit-fly brain use dopamine. Comparing those linked to sexual function in elderly 40-day-old male flies and sprightly 10-day-old flies, Fu found the older neurones carried 10 times less dopamine. Boosting levels lengthened the time the older flies spent trying to mate. There are obviously big differences between a man's brain and that of a male Drosophila, but Fu says that the new results could provide a useful starting point for in-depth studies that may have clinical implications. For instance, that research might eventually identify ways to fine-tune dopamine levels in humans, perhaps to reverse age-related declines in sexual drive, or even to suppress an overactive libido. We already have therapies for treating male sexual dysfunction – notably the drug viagra. But probing the link between dopamine and sexual dysfunction is still important. For instance, dopamine-replacement therapy is one of the most effective treatments for Parkinson's disease – but the therapy can lead to harmful compulsive sexual behaviour. But Wendi Neckameyer at the Saint Louis University School of Medicine in Missouri isn't sure we should talk about potential implications for men just yet – it's enough to say that the researchers "have begun to tease out an incredibly complex neural circuit", she says. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 21115 - Posted: 07.01.2015

by Curtis Abraham A step forward for equal LGBT rights in Africa. Last week, the influential Academy of Science of South Africa (ASSAf) published a study on the science of human sexual diversity. A comprehensive review of recent scientific papers on the subject, it concluded that sexual behaviour is naturally varied, and discrimination unjustified. It stated that there is no evidence that orientation can be altered by therapy or that being gay is contagious. The report also sets straight the idea that homosexuality is a Western malaise: "There is no basis for the view that homosexuality is 'un-African' either in the sense of it being a 'colonial import', or on the basis that prevalence of people with same-sex or bisexual orientations is any different in African countries compared to countries on any other continent." Going further, the report asserted not only that tolerance of sexual diversity benefits communities but it positively affects public health, civil society and long-term economic growth. Zero tolerance Launched at the Seventh South African AIDS Conference in Durban, the study comes a year after the Ugandan government passed a law imposing a life sentence on anyone who has sexual relations with someone of the same sex. Other countries, including Burundi, Cameroon and Nigeria, then passed similar anti-gay laws. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21071 - Posted: 06.18.2015

Tom Bawden The mystery behind the nightingale’s beautiful song has been revealed, with scientists finding that male birds sing complex notes to prove to females that they would be a good father to their children. Nightingales use their songs to advertise their family values, according to new research which discovers that the better the singer, the more support they are likely to offer their young family by feeding and defending them from predators. But while the beauty comes from the complexity of the song, the effect it has on the females is based on something far more mundane – the amount of effort the singer has put into his performance. Researchers at the Freie Universitat Berlin found that complicated choral arrangements are much harder to sing, especially when they include frequent appearances of long buzzing sounds and require the bird to be in good physical condition. “We don’t think the female is concerned with the beauty of the song but rather the information encoded in the song that tells her about the singer’s characteristics – his age, where he was raised, the strength of his immune system and how motivated he is to contribute to bringing up the young,” Professor Silke Kipper, one of the report’s authors, told The Independent. “The songs can also be a good indication of the bird’s ability to learn, which is another important characteristic of a good parent.” © independent.co.uk

Related chapters from BP7e: 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: 21067 - Posted: 06.18.2015

by Michael Sean Pepper and Beverley Kramer People who are attracted to others of the same sex develop their orientation before they are born. This is not a choice. And scientific evidence shows their parents cannot be blamed. Research proving that there is biological evidence for sexual orientation has been available since the 1980s. The links have been emphasised by new scientific research. In 2014, researchers confirmed the association between same-sex orientation in men and a specific chromosomal region. This is similar to findings originally published in the 1990s, which, at that time, gave rise to the idea that a “gay gene” must exist. But this argument has never been substantiated, despite the fact that studies have shown that homosexuality is a heritable trait. Evidence points towards the existence of a complex interaction between genes and environment, which are responsible for the heritable nature of sexual orientation. These findings are part of a report released by the Academy of Science South Africa. The report is the outcome of work conducted by a panel put together in 2014 to evaluate all research on the subject of sexual orientation done over the last 50 years. It did this against the backdrop of a growing number of new laws in Africa which discriminate against people attracted to others of the same sex. The work was conducted in conjunction with the Ugandan Academy of Science.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21049 - Posted: 06.15.2015

by Clare Wilson The first drug for treating low sexual desire in women looks set to go on sale in the US next year Flibanserin, sometimes called the female Viagra, was approved by 18 votes to 6 by a US Food and Drug Administration advisory panel yesterday, although some of the committee members had doubts about the drug's risks and benefits. They required that certain "risk-management options" be put in place, on top of the usual list of side effects listed in the medicine's patient information leaflet. We have yet to hear what this means, but options include doctors having to verbally warn women not to drink alcohol or use various other medicines when taking the drug. The FDA's final say is due by August, but it usually follows the decision of its advisory panel. Assuming it gets the go-ahead, manufacturer Sprout Pharmaceuticals of Raleigh, North Carolina, plans to give the drug the brand-name Addyi, and has promised not to advertise the product directly to patients – which is normally allowed in the US – for the first 18 months it goes on sale. Addyi is no Viagra though – women would have to take it every day, whether or not they want sex. And, while the famous little blue pill works by increasing blood flow to the genitals, this new drug instead alters brain chemistry, affecting receptors for various signalling chemicals including serotonin and dopamine. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21020 - Posted: 06.06.2015

By Elahe Izadi Researchers classified two new species of Dusky Antechinus, mouse-like creatures that engage in suicidal reproduction, and published their findings last week in the peer-reviewed journal Memoirs of the Queensland Museum -- Nature. The Mainland Dusky Antechinus, found in southeastern Australia, has been elevated from sub-species to a distinct species. And the newly discovered Tasman Peninsula Dusky Antechinus, found in southeastern Tasmania, already faces the threat of extinction due in part to loss of habitat and feral pests, researchers said. Their proclivity for ferocious, suicidal sex frenzies aren't helping them any. "The breeding period is basically two to three weeks of speed-mating, with testosterone-fueled males coupling with as many females as possible, for up to 14 hours at a time," lead author Andrew Baker of the Queensland University of Technology said in a release. All of that testosterone "triggers a malfunction in the stress hormone shut-off switch" for the males, Baker said. The males then get so stressed out that their immune systems fail, and they die before the females actually give birth. Suicidal reproduction -- or semelparity-- is rare in mammals, and has so far just been documented in these kinds of marsupials.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21015 - Posted: 06.03.2015

Allie Wilkinson For many species, reproduction is a duet between male and female. Now, for the first time, scientists report evidence of 'virgin birth' in a wild vertebrate, the smalltooth sawfish. The fish (Pristis pectinata) normally reproduces sexually, requiring contributions from both sexes. But the latest analysis estimates that nearly 4% of sawfish in a Florida estuary were born without any genetic contribution from a male, in a phenomenon known as parthenogenesis. This asexual reproduction is rare in vertebrates, and had previously been observed only in a handful of species in captivity, including snakes collected from the wild1 and Komodo dragons2. The latest findings appear in the 1 June issue of Current Biology3. Smalltooth sawfish are one of five large ray species that have chainsaw-like appendages protruding from their faces, and are in the same subclass as sharks. The smalltooth sawfish was once abundant along the US eastern and southern coastlines from North Carolina to Texas, but overfishing and coastal development have drastically reduced its numbers. The critically endangered fish are now found only off the coast of southwest Florida. Researchers discovered evidence of 'virgin births' among the sawfish while conducting a routine genetic analysis to determine whether they were inbreeding. Some of the 190 sawfish sampled in a Florida estuary showed unusually high levels of relatedness to other fish in the same population. © 2015 Nature Publishing Group

Related chapters from BP7e: 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: 21009 - Posted: 06.02.2015

By ANDREW POLLACK Is sexual desire a human right? And are women entitled to a little pink pill to help them feel it? Those questions are being raised in a campaign that is pressing the Food and Drug Administration to approve a pill aimed at restoring lost libido in women. The campaign, backed by the drug’s developer and some women’s groups, accuses the F.D.A. of gender bias for approving Viagra and 25 other drugs to help men have sex, but none for women. “Women have waited long enough,” the effort, known as Even the Score, says in an online petition that has gathered more than 40,000 signatures. “In 2015, gender equality should be the standard when it comes to access to treatments for sexual dysfunction.” The drug, flibanserin, has been rejected twice by the F.D.A. on the grounds that its very modest effectiveness was outweighed by side effects like sleepiness, dizziness and nausea. The first rejection, in 2010, followed a decision by a committee of outside advisers to the agency who unanimously opposed approval. On Thursday, F.D.A. advisers will once again consider whether flibanserin should be approved. Sprout Pharmaceuticals, which now owns the drug, has submitted new data, including a study to demonstrate that the pill does not impair driving. Still, approval might hinge on whether the F.D.A. agrees to interpret the old data in a new way and whether the politics of such drugs has changed. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21002 - Posted: 06.01.2015

By Sarah C. P. Williams Here’s an easy way to tell if a female warbler is a year-round resident of the tropics or just a visiting snowbird: Females from species that spend their lives near the equator tend to have brighter plumage more typical of male birds. In contrast, females who fly north for the summer appear drab compared with their male counterparts. In the past, researchers thought the difference was due to the shorter breeding season in the north, hypothesizing that migrating males evolved bright colors to better compete for mates. But a new study hints that northern-breeding females may have evolved to be less colorful than males in order to be less conspicuous to predators during their long migrations. Researchers at Trinity University in San Antonio, Texas, studied the coloring, migration patterns, breeding locales, and ancestry of 109 warbler species. Migration distance, not the length of the breeding season, was the best predictor of color contrasts between male and female birds, they report online today in the Proceedings of the Royal Society B. Female bay-breasted warblers (Setophaga castanea), for instance, which migrate about 7000 kilometers between their breeding grounds in North America and their wintering grounds in the Caribbean, are a dull gray and white, whereas males boast more showy yellows and browns. But both male and female slate-throated redstarts (Myioborus miniatus), like the one shown above, flaunt bright colors in their year-round tropical homes in Mexico and Central America. For migrating warblers, the researchers hypothesize that the breeding benefits of brighter male colors outweigh the threat of being spotted by a hungry predator. © 2015 American Association for the Advancement of Science.

Related chapters from BP7e: 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: 20984 - Posted: 05.27.2015