Links for Keyword: Sexual Behavior

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 1310

Shankar Vedantam Girls often outperform boys in science and math at an early age but are less likely to choose tough courses in high school. An Israeli experiment demonstrates how biases of teachers affect students. RENEE MONTAGNE, HOST: At early ages, girls often outperform boys in math and science classes. Later, something changes. By the time they get into high school, girls are less likely than boys to take difficult math courses and less likely, again, to go into careers in science, technology, engineering or medicine. To learn more about this, David Greene spoke with NPR social science correspondent Shankar Vedantam. SHANKAR VEDANTAM, BYLINE: Well, the new study suggests, David, that some of these outcomes might be driven by the unconscious biases of elementary school teachers. What's remarkable about the new work is it doesn't just theorize about the gender gap, it actually has very hard evidence. Edith Sand at Tel Aviv University and her colleague, Victor Lavy, analyzed the math test scores of about 3,000 students in Tel Aviv. When the students were in sixth grade, the researchers got two sets of math test scores. One set of scores were given by the classroom teachers, who obviously knew the children whom they were grading. The second set of scores were from external teachers who did not know if the children they were grading were either boys or girls. So the external teachers were blind to the gender of the children. © 2015 NPR

Related chapters from BP7e: 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: 21374 - Posted: 09.02.2015

They are rather diminutive to be kings of the jungle, but two species of mirid bug make sounds similar to the roars of big cats. These calls have never before been heard in insects, and we’re not sure why, or how, the insects produce the eerie calls. The roars are too weak to be heard by humans without a bit of help. But Valerio Mazzoni of the Edmund Mach Foundation in Italy and his team made them audible by amplifying them using a device called a laser vibrometer. The device detects the minute vibrations that the bugs produce on the leaves on which they live. “When you listen to these sounds through headphones you’d think you were next to a tiger or lion,” Mazzoni. The team found that when two males were introduced on the same leaf, they seemed to compete in roaring duets. When one insect heard a roar, it always sounded its own, apparently in response. This suggests that, as in big cats, the roars might serve to establish dominance or attract females. Female mirids don’t seem to roar. But unlike the roars of big cats, the sounds produced by bugs are transmitted through the solid material beneath their feet, usually a leaf, rather than by the vibration of air molecules. Thousands of insect species communicate through such vibration, but these roars are unlike any other known insect noise. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: 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: 21357 - Posted: 08.29.2015

Nell Greenfieldboyce Picking a mate can be one of life's most important decisions. But sometimes people make a choice that seems to make no sense at all. And humans aren't the only ones — scientists have now seen apparently irrational romantic decisions in frogs. Little tungara frogs live in Central America, and they're found everywhere from forests to ditches to parking lot puddles. These frogs are only about 2 centimeters long, but they are loud. The males make calls to woo the females. Amanda Lea, a biologist in the laboratory of Mike Ryan at the University of Texas, Austin, says past studies have given scientists a pretty good idea of what the females find appealing. "They tend to like longer calls. They also like lower-frequency calls," says Lea. "Then, the other thing that's a really big one for these gals is the 'call rate.' They love faster call rates. The faster a male can call, the better." But in real life, love is complicated. Female frogs face countless suitors. So Lea and Ryan wondered: Would a female really always pick the male that scored highest on the froggy love-call meter? To find out, they put female frogs in a room with some loudspeakers. From one speaker the scientists played a recording of frog call that had a really fast rate. But other features in this voice were less attractive. Then the researchers played a second, different call for the female frogs. This voice was more attractive, but it was slower. The ladies had to make a choice. "They have two traits to evaluate," Lea explains. "They have the call rate and they have the attractiveness of the call." © 2015 NPR

Related chapters from BP7e: 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: 21351 - Posted: 08.28.2015

By Melinda Wenner Moyer As many as four out of every five pregnant women say that they suffer from “pregnancy brain”—deficits in memory and cognitive ability that arise during pregnancy, making women more forgetful and slow-witted. Yet studies on the phenomenon have generally not supported these claims: although some have found evidence of problems on certain types of tasks, others, including a recent paper published by researchers in Utah, have found no signs of cognitive problems at all. Some experts believe that pregnancy brain and its postnatal cousin, “baby brain,” could largely be a product of confirmation bias: pregnant women and new moms expect to experience brain fog and therefore believe they are actually affected. Others argue that the mental symptoms might simply be too difficult to confirm in a laboratory setting. In the most recent study, researchers at Brigham Young University gave cognitive and neuropsychological tests to 21 women in their third trimester of pregnancy and then tested them again six months after they gave birth. They administered the same tests at similar intervals to 21 women who had never been pregnant. They found no differences between the groups no matter when they were tested, including before and after giving birth. These findings mesh with those from a 2003 study, which found that pregnant women did not score differently from nonpregnant women on tests of verbal memory, divided attention and focused attention. “There is variety in the results, but overall most studies suggest there are few to no memory impairments associated with pregnancy,” says Michael Larson, a psychologist at Brigham Young and a co-author of the recent paper. He thinks the reason the myth persists may be that women selectively look for evidence that supports the cultural expectation. © 2015 Scientific American

Related chapters from BP7e: 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: 21344 - Posted: 08.27.2015

By Esther Landhuis The birth of a child leaves its mark on the brain. Most investigations of these changes have focused on mothers, but scientists have recently begun looking more closely at fathers. Neural circuits that support parental behaviors appear more robust in moms a few weeks after the baby is born, whereas in dads the growth can take several months. A study in Social Neuroscience analyzed 16 dads several weeks after their baby's birth and again a few months later. At each check, the researchers administered a multiple-choice test to check for signs of depression and used MRI to image the brain. Compared with the earlier scans, MRI at three to four months postpartum showed growth in the hypothalamus, amygdala and other regions that regulate emotion, motivation and decision making. Furthermore, dads with more growth in these brain areas were less likely to show depressive symptoms, says first author Pilyoung Kim, who directs the Family and Child Neuroscience Lab at the University of Denver. Although some physiological brain changes are similar in new moms and dads, other changes seem different and could relate to the roles of each parent, says senior author James Swain, a psychiatrist at the University of Michigan (brain diagrams below). A 2014 behavioral study of expectant fathers showed that midpregnancy ultrasound imaging was a “magic moment” in the dads' emerging connection with their baby. Yet the emotional bond was different than it is in expectant moms. Instead of thinking about cuddling or feeding the baby, dads-to-be focused on the future: they imagined saving money for a college fund or walking down the aisle at their daughter's wedding. © 2015 Scientific American

Related chapters from BP7e: 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: 21334 - Posted: 08.25.2015

By Hanae Armitage The libido enhancement drug flibanserin (trade name Addyi) took center stage last week after winning long-sought approval from the U.S. Food and Drug Administration (FDA). The coverage from advocates and nonbelievers has run the gamut—advice, caution, and criticism likely to confuse undecided—but curious—onlookers. But exactly how Addyi drums up sex drive is still murky. The drug has a long backstory. It was originally investigated in 1995 by pharmacologist Franco Borsini and a team of researchers at Boehringer Ingelheim Italia in Milan as an antidepressant because of its ability to regulate neurotransmitters—the brain’s chemical-signaling molecules. In particular, the team suspected that the drug regulated three key neurotransmitters thought to influence mood: serotonin, dopamine, and norepinephrine. A clinical trial found it did little to alleviate depression, but did seem to have an effect on mood. It just wasn’t the mood the researchers were expecting. These early trials tipped clinicians to flibanserin’s more prominent role in sexual health, as female subjects had higher scores on the Arizona Sexual Experience Scale, a survey that asks participants to rate their satisfaction on a variety of sexual health topics, like how often participants felt sexual desire and how intense that desire was. A separate group of researchers, also at Boehringer Ingelheim, completed their first clinical trials to explore flibanserin as a libido-enhancer in 2008. They measured levels of desire through a journal-based evaluation in which subjects recorded their levels of sexual drive on a daily basis. But FDA twice concluded that the resulting increases in libido were not statistically significant, and regulators were wary of potentially dangerous side effects like dizziness, sleepiness, nausea, and fainting. © 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: 21332 - Posted: 08.25.2015

Richard A. Friedman THANKS to Caitlyn Jenner, and the military’s changing policies, transgender people are gaining acceptance — and living in a bigger, more understanding spotlight than at any previous time. We’re learning to be more accepting of transgender individuals. And we’re learning more about gender identity, too. The prevailing narrative seems to be that gender is a social construct and that people can move between genders to arrive at their true identity. But if gender were nothing more than a social convention, why was it necessary for Caitlyn Jenner to undergo facial surgeries, take hormones and remove her body hair? The fact that some transgender individuals use hormone treatment and surgery to switch gender speaks to the inescapable biology at the heart of gender identity. This is not to suggest that gender identity is simply binary — male or female — or that gender identity is inflexible for everyone. Nor does it mean that conventional gender roles always feel right; the sheer number of people who experience varying degrees of mismatch between their preferred gender and their body makes this very clear. In fact, recent neuroscience research suggests that gender identity may exist on a spectrum and that gender dysphoria fits well within the range of human biological variation. For example, Georg S. Kranz at the Medical University of Vienna and colleagues elsewhere reported in a 2014 study in The Journal of Neuroscience that individuals who identified as transsexuals — those who wanted sex reassignment — had structural differences in their brains that were between their desired gender and their genetic sex. © 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: 21329 - Posted: 08.24.2015

By Kazi Stastna The U.S. approval of a pill to treat low libido in women has whipped up a whirlwind of debate and raised questions about whether the so-called female Viagra addresses the real reasons for lack of sexual desire. The U.S. Food and Drug Administration last week approved flibanserin, to be sold under the name Addyi starting in October, for the treatment of hypoactive sexual desire disorder (HSDD) among premenopausal women — some two decades after Viagra was approved for the treatment of male erectile dysfunction. Sprout Pharmaceuticals pitched flibanserin as a drug that would finally give women with sexual dysfunction similar treatment options to men and bused dozens of women to FDA hearings in Maryland to attest to its benefits and plead for its approval in what some saw as a heavy-handed and misleading public relations campaign. The FDA gave flibanserin the OK after twice rejecting it and despite concerns about its risks and modest efficacy because it said women suffering distress from low libido have an "unmet medical need." Days after it did, Canadian pharmaceutical company Valeant offered to buy Sprout for $1 billion US and said it will apply to get flibanserin approved in Canada and other countries. Although often likened to Viagra, flibanserin was created as an antidepressant and works on the brain while erectile dysfunction medications stimulate blood flow to the penis. Critics argue it's an ineffectual pharmacological solution for a problem better treated with relationship counselling, sex therapy and behavioural changes. "Their suffering is real, but the women who testified had a lot of different stories, and some of those stories were very good reasons for having low libido, including having six children, having a one-year-old, having had breast cancer treatment …," says Adriane Fugh-Berman, associate professor of pharmacology and physiology at Georgetown University in Washington, D.C., and director of PharmedOut, a pharmaceutical marketing watchdog group. ©2015 CBC/Radio-Canada.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 21328 - Posted: 08.24.2015

By ANDREW POLLACK The first prescription drug to enhance women’s sexual drive won regulatory approval on Tuesday, clinching a victory for a lobbying campaign that had accused the Food and Drug Administration of gender bias for ignoring the sexual needs of women. The drug — Addyi from Sprout Pharmaceuticals — is actually the first drug approved to treat a flagging or absent libido for either sex. Viagra and other drugs available for men are approved to help achieve erections, or to treat certain deficiencies of the hormone testosterone, not to increase desire. Advocates who pressed for approval of Addyi, many of them part of a coalition called Even the Score, said that a drug to improve women’s sex lives was long overdue, given the many options available to men. “This is the biggest breakthrough for women’s sexual health since the pill,” said Sally Greenberg, executive director of the National Consumers League. But critics said the campaign behind Addyi had made a mockery of the system that regulates pharmaceuticals and had co-opted the women’s movement to pressure the F.D.A. into approving a drug that was at best minimally effective and could cause side effects like low blood pressure, fainting, nausea, dizziness and sleepiness. In announcing the approval, Dr. Janet Woodcock, a senior F.D.A. official, said the agency was “committed to supporting the development of safe and effective treatments for female sexual dysfunction.” The F.D.A. decision on Tuesday was not a surprise since an advisory committee of outside experts had recommended by a vote of 18 to 6 in June that the drug be approved, albeit with precautions required to try to limit the risks and ensure that it was not overused. © 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: 21311 - Posted: 08.19.2015

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