By Erin Blakemore There’s growing consensus on the danger of sport-related concussion — and how to treat athletes after head injuries. But the research at the heart of those recommendations has a fatal flaw, a new study suggests: It relies almost exclusively on male athletes. In a review in the British Journal of Sports Medicine, a national team of medical and concussion experts looked at 171 concussion studies cited by the three most influential consensus and position statements on sport-related concussion. These documents update professionals on how to treat athletes with concussions, providing important protocols for clinicians and setting the agenda for future research. Although the statements define the standard of care, the study suggests, they are based on data that largely excludes female athletes. Participants in the underlying studies were 80.1 percent male. Among the studies, 40.3 percent didn’t look at female athletes at all; only 25 percent of them had roughly equal male and female participation. Researchers said there could be several reasons for the disparity such as women’s historic exclusion from sports and professional sports organizations with no female counterpart. Women’s sports are underrepresented among groups that sponsor concussion research, they write. Bias in the sciences could have an effect, too: women are still underrepresented in both university faculties and scientific research. Because of the research gap, it isn’t yet clear whether females respond to concussions differently than males. Both sex and gender can cause medical conditions to develop — and be experienced, reported and treated — differently.

Keyword: Brain Injury/Concussion; Sexual Behavior
Link ID: 28432 - Posted: 08.13.2022

By Sara Goudarzi Life isn’t always easy for little mouse pups: Hours to days after they are born, the squirmy babies, who can’t hear or see, can roll or stumble away from their nest. Cold and lonely, they call out to their mother. Luckily, Mom snaps into action to ensure the adventures of the little ones are short-lived. Grabbing each pup by the skin on their backs, Mama mouse brings each baby back home to safety. The mom’s behavior is innate, burnt into the mouse brain, and requires no training. But where in the brain does it happen and how does the brain process or execute it? And what happens in those rare cases when the animal brain doesn’t properly execute such behavior? That’s what Stephen Shea is trying to answer in mice, with hopes that it may someday be applicable to humans. Shea, an associate professor at Cold Spring Harbor Laboratory, discovered that this innate mothering behavior corresponds to the firing of cells in a region of the brain called locus coeruleus, a cluster of cells that can be found in the brainstem of all vertebrates. Locus coeruleus is also the source of noradrenaline, a chemical that affects some key brain functions. Shea’s work has greater implications. He hopes that understanding the brain circuits that facilitate this very simple action could be a window into how disruptions in wiring affect social behavior, and a key into understanding inappropriate social interactions, such as those observed in people with autism spectrum disorders. And it may even shed some light on the iconic debate about whether creatures are shaped by nature or nurture. © 2022 NautilusThink Inc,

Keyword: Sexual Behavior
Link ID: 28424 - Posted: 08.06.2022

By Virginia Morell In the summer of 2013, dolphin researcher Nicole Danaher-Garcia spotted something rare and remarkable in the animal world. As she stood on top of the bridge of a sport fishing yacht near Bimini in the Bahamas, she spied 10 adult Atlantic spotted dolphins she had never seen before—speeding into the waters of another group of dolphins. Most mammals attack intruders, but war wasn’t on the menu that day. Instead, the newcomers—eventually 46 in all—joined up with the resident dolphins, some 120 in number. Today, the two groups of Atlantic spotted dolphins (Stenella frontalis) have partially integrated, diving and swimming together, forming fast friendships, and likely even mating. It’s a “striking” display of tranquility between animals scientists usually consider rivals, says Richard Wrangham, a primatologist at Harvard University who was not involved with the study. Most mammals fight to protect mates and other resources if they encounter strangers entering their territory, he notes. This research, he says, may ultimately lead to a better understanding of the evolution of peacefulness. Danaher-Garcia, a behavioral ecologist, and her colleagues at the Dolphin Communication Project observed the two groups of dolphins in Bimini for 5 years, carrying out nearly 300 surveys. At first, the scientists only saw one small group of mixed Bimini and newcomer dolphins. But the next year, the scientists spotted a larger group of males and females of all ages from both communities mixing without “any signs of aggression,” she says. The dolphins continued their friendly behaviors through 2018, leading the team to suspect the two groups were merging. (Because of COVID-19 concerns, the scientists put their studies on hold in 2020.) The scientists discovered the newcomers had migrated from Little Bahama Bank, an area some 160 kilometers to the north known for its shallow seas, coral reefs, and sand banks. They were part of the White Sand Ridge (WSR) spotted dolphin community that another scientific team has been studying since the mid-1980s. © 2022 American Association for the Advancement of Science.

Keyword: Aggression; Sexual Behavior
Link ID: 28419 - Posted: 08.03.2022

By Gina Kolata It’s been known for more than half a century that many men lose their Y chromosomes as they age. But no one knew if it really mattered. The loss of Y could just be a sign of aging, like gray hair, with no clinical relevance. Now, though, researchers report that it can matter. Very much. A new study using male mice genetically engineered to lose their Y chromosomes provides insight. The paper, published on Thursday in the journal Science, found that when the Y chromosome was gone from blood cells in those mice, scar tissue built up in the heart, leading to heart failure and a shortened life span. Because there was a direct cause-and-effect relationship between the loss of Y and ailments of aging in the mice, the study bolsters the notion that the same thing can happen in human males. Researchers have documented an increase in risk for chronic diseases like heart disease and cancer related to loss of the Y chromosome in many studies over the years, including the new one, which used data from a large genetic study of the British population. The loss of Y could even account for some of the difference between the life spans of men and women, the authors of the Science study say. Other investigators not associated with the work were impressed. “The authors really nailed it here,” said Dr. Ross Levine, the deputy physician in chief for translational research at Memorial Sloan Kettering Cancer Center. “It’s super important work.” The inspiration for the new research came when Lars Forsberg, a researcher at Uppsala University, ran into a former professor on a bus in Uppsala, Sweden, in 2013. They began talking, and the professor told Dr. Forsberg that the Y chromosomes in fruit flies were more important than previously appreciated. Dr. Forsberg was intrigued. He had never paid much attention to the loss of Y chromosomes. Males have one X and one Y (females have two X’s), and nearly all the genes used by male cells are genes on the X. Dr. Forsberg had shared the common view that the Y chromosome was pretty much a genetic wasteland. © 2022 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28400 - Posted: 07.16.2022

By Veronique Greenwood Human beings maintain the polite fiction that we’re not constantly smelling one another. Despite our efforts to the contrary, we all have our own odors, pleasant and less so, and if we are like other land mammals, our particular perfume might mean something to our fellow humans. Some of these, like the reek of someone who hasn’t bathed all month, or the distinctive whiff of a toddler who is pretending they didn’t just fill their diaper, are self-explanatory. But scientists who study human olfaction, or your sense of smell, wonder if the molecules wafting off our skin may be registering at some subconscious level in the noses and brains of people around us. Are they bearing messages that we use in decisions without realizing it? Might they even be shaping whom we do and don’t like to spend time around? Indeed, in a small study published Wednesday in the journal Science Advances, researchers investigating pairs of friends whose friendship “clicked” from the beginning found intriguing evidence that each person’s body odor was closer to their friend’s than expected by chance. And when the researchers got pairs of strangers to play a game together, their body odors predicted whether they felt they had a good connection. There are many factors that shape whom people become friends with, including how, when or where we meet a new person. But perhaps one thing we pick up on, the researchers suggest, is how they smell. Scientists who study friendship have found that friends have more in common than strangers — not just things like age and hobbies, but also genetics, patterns of brain activity and appearance. Inbal Ravreby, a graduate student in the lab of Noam Sobel, an olfaction researcher at the Weizmann Institute of Science in Israel, was curious whether particularly swift friendships, the kind that seem to form in an instant, had an olfactory component — whether people might be picking up on similarities in their smells. © 2022 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28382 - Posted: 06.25.2022

By Emily Bazelon Scott Leibowitz is a pioneer in the field of transgender health care. He has directed or worked at three gender clinics on the East Coast and the Midwest, where he provides gender-affirming care, the approach the medical community has largely adopted for embracing children and teenagers who come out as transgender. He also helps shape policy on L.G.B.T. issues for the American Academy of Child and Adolescent Psychiatry. As a child and adolescent psychiatrist who is gay, he found it felt natural to work under the L.G.B.T. “umbrella,” as he put it, aware of the overlap as well as the differences between gay and trans identity. It was for all these reasons that Leibowitz was selected, in 2017, to be a leader of a working group of seven clinicians and researchers drafting a chapter on adolescents for a new version of guidelines called the Standards of Care to be issued by the World Professional Association for Transgender Health (WPATH). The guidelines are meant to set a gold standard for the field of transgender health care, and this would be the first update since 2012. What Leibowitz and his co-authors didn’t foresee, when they began, was that their work would be engulfed by two intersecting forces: a significant rise in the number of teenagers openly identifying as transgender and seeking gender care, and a right-wing backlash in the United States against allowing them to medically transition, including state-by-state efforts to ban it. During the last decade, the field of transgender care for youth has greatly shifted. A decade ago, there were a handful of pediatric gender clinics in the United States and a dozen or so more in other countries. The few doctors and therapists who worked in them knew one another, and the big debate was whether kids in preschool or elementary school should be allowed to live fully as the gender they identified as when they strongly and consistently asserted their wishes. Now there are more than 60 comprehensive gender clinics in the United States, along with countless therapists and doctors in private practice who are also seeing young patients with gender-identity issues. The number of young people who identify as transgender nationally is about 300,000, according to a new report by the Williams Institute, a research center at U.C.L.A.’s law school, which is much higher than previous estimates. In countries that collect national data, like the Netherlands and Britain, the number of 13-to-17-year-olds seeking treatment for gender-identity issues has also increased, from dozens to hundreds or thousands a year. © 2022 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 28375 - Posted: 06.15.2022

By Erika Engelhaupt To Charles Darwin, nature had a certain order. And in that order, males always came out on top. They were the leaders, the innovators, the wooers and the doers. “The males of almost all animals have stronger passions than the females,” Darwin wrote in 1871. “The female, on the other hand, with the rarest of exceptions, is less eager.” The founder of evolutionary theory posited that throughout the animal kingdom, males are active, females are passive, and that’s pretty much that. Females, in sum, are boring. That’s poppycock, Lucy Cooke writes in her latest book, Bitch. This blinkered view of nature as a man’s world was conceived and promulgated by Victorian men who imposed their values and world view on animals, she says. Cooke, a documentary filmmaker and the author of The Truth About Animals and two children’s books (SN: 4/14/18, p. 26), has traveled the world and met scientists who are exposing the truth about the sexes. She takes readers on a wild ride as she observes the ridiculous mating rituals of sage grouse, searches for orca poop (to monitor sex hormones) and watches female lemurs boss around males. Through such adventures, Cooke learns that females are anything but boring. “Female animals are just as promiscuous, competitive, aggressive, dominant and dynamic as males,” she writes. That may not sound radical to today’s feminists, but in the field of evolutionary biology, such a pronouncement has long bordered on the heretical. Generations of biologists have focused on male behavior and physiology, on the assumption that females are little more than baby-making machines to be won over by the strongest, showiest males. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28372 - Posted: 06.15.2022

Meghan Hoyer and Tim Meko When Vanderbilt University psychiatrist Jonathan Metzl learned that the perpetrator of the Uvalde, Tex., school massacre was a young man barely out of adolescence, it was hard not to think about the peculiarities of the maturing male brain. Salvador Rolando Ramos had just turned 18, eerily close in age to Nikolas Cruz, who had been 19 when he shot up a school in Parkland, Fla. And to Adam Lanza, 20, when he did the same in Newtown, Conn. To Seung-Hui Cho, 23, at Virginia Tech. And to Eric Harris, 18, and Dylan Klebold, 17, in Columbine, Colo. Teen and young adult males have long stood out from other subgroups for their impulsive behavior. They are far more reckless and prone to violence than their counterparts in other age groups, and their leading causes of death includes fights, accidents, driving too fast, or, as Metzl put it, “other impulsive kinds of acts.” “There’s a lot of research about how their brains are not fully developed in terms of regulation,” he said. Perhaps most significantly, studies show, the prefrontal cortex, which is critical to understanding the consequences of one’s actions and controlling impulses, does not fully develop until about age 25. In that context, Metzl said, a shooting “certainly feels like another kind of performance of young masculinity.” In coming weeks and months, investigators will dissect Ramos’s life to try to figure out what led him to that horrific moment at 11:40 a.m. Tuesday, May 24 when he opened fire on a classroom full of 9- and-10-year-olds at Robb Elementary School. Although clear answers are unlikely, the patterns that have emerged about mass shooters in the growing databases, school reports, medical notes and interview transcripts show a disturbing confluence between angry young men, easy access to weapons and reinforcement of violence by social media. © 1996-2022 The Washington Post

Keyword: Aggression; Hormones & Behavior
Link ID: 28352 - Posted: 06.04.2022

By Jack Tamisiea Sign up for Science Times Get stories that capture the wonders of nature, the cosmos and the human body. Get it sent to your inbox. Since the days of Charles Darwin, the long necks of giraffes have been a textbook example of evolution. The theory goes that as giraffe ancestors competed for food, those with longer necks were able to reach higher leaves, getting a leg — or neck — up over shorter animals. But a bizarre prehistoric giraffe relative reveals that fighting may have driven early neck evolution in addition to foraging. In a study published Thursday in Science, a team of paleontologists described Discokeryx xiezhi, a giraffe ancestor, as having helmet-like headgear and bulky neck vertebrae. Discokeryx was adapted to absorb and deliver skull-cracking collisions to woo mates and vanquish rivals. “It shows that giraffe evolution is not just elongating the neck,” said Jin Meng, a paleontologist at the American Museum of Natural History and co-author of the new study. “Discokeryx goes in a totally different direction.” Dr. Meng and his colleagues discovered the fossils in an outcrop of rock in northwestern China called the Junggar Basin. Around 17 million years ago, this area was an expanse of savannas and forests home to an array of large mammals like shovel-tusked elephants, short-horned rhinoceroses and burly bear dogs. While exploring this bonebed in 1996, Dr. Meng stumbled across a hunk of skull. He could tell it was a mammalian braincase, but the top was flattened like an iron press. Without more of the animal’s skeleton, Dr. Meng and his colleagues referred to it as the “strange beast.” © 2022 The New York Times Company

Keyword: Evolution; Aggression
Link ID: 28350 - Posted: 06.04.2022

By Amber Dance Suppose a couple has two children, a boy and a girl. Chances are, they’ll both grow up with typical, healthy brains. But should either diverge from the usual route of brain development, or suffer mental health issues, their paths are likely to be different. The son’s differences might show up first. All else being equal, he’s four times more likely than his sister to be diagnosed with autism. Rates of other neurodevelopmental conditions and disabilities are also higher in boys. As he grows into a young man, his chances of developing schizophrenia will be two to three times higher than hers. When the siblings hit puberty, those relative risks will flip. The sister will be almost twice as likely to experience depression or an anxiety disorder. Much later in life, she’ll be at higher risk of developing Alzheimer’s disease. Those trends are not hard and fast rules, of course: Men can and do suffer from depression and Alzheimer’s; some girls develop autism; women aren’t immune to schizophrenia. Male and female brains are more alike than they are different. But scientists are learning that there’s more to these different risk profiles than, say, the pressures women face in a patriarchal society or the fact that women tend to live longer, giving diseases of aging time to develop. Subtle biological differences between male and female brains, and bodies, are important contributors. To explain these sex differences, there are some obvious places to look. The female’s two X chromosomes, to the male’s single copy, is one. Differing sex hormones — primarily testosterone in males and estrogen in females — is another. But a steadily growing body of research points to a less obvious influence: the cells and molecules of the immune system. © 2022 Annual Reviews

Keyword: Sexual Behavior; Neuroimmunology
Link ID: 28345 - Posted: 06.01.2022

NPR's Sacha Pfeiffer talks with Eliot Schrefer, author of Queer Ducks (And Other Animals): The Natural World of Animal Sexuality. It's about how "natural sex" may not be as binary as some think. SACHA PFEIFFER, HOST: At its worst, a nonfiction science book about animal sexuality could read like a dry biology textbook. But that's not the kind of book Eliot Schrefer wrote. His book, called "Queer Ducks (And Other Animals): The Natural World Of Animal Sexuality," is designed to be teenager-friendly, for one thing. It's a young adult book filled with comics and humor and accessible science, and it's filled with research on the diversity of sexual behavior in the animal world. Eliot Schrefer is with us to explain more. Welcome, Eliot. ELIOT SCHREFER: Hi. I'm really happy to be here. PFEIFFER: We're glad to have you. I really liked the way you structured your book. It's basically an animal per chapter, in a way. But you also have these wonderful illustrations. You have interviews with scientists. Tell us a little bit about how you decided to make it accessible because, again, you're aiming for adolescents, as I understand it, in a nonfiction way, and they might be inclined to think nonfiction equals boring, dry textbook. SCHREFER: Right. I sort of imagine, like, we're kind of sitting in the science classroom, passing notes back and forth, and it even comes down to the doodles. There's an artist, Jules Zuckerberg, who did a one-page comic for each of the animal species that we discuss. So it's - the premise is that it's an animal GSA. PFEIFFER: A gender sexuality alliance meeting. SCHREFER: That's right. And so they're each taking a turn introducing themselves. And so the bonobo takes a turn introducing how her family works, and then the doodlebug and the dolphin and so on. PFEIFFER: Yeah, they're really great. They make the book really accessible. As we said, every chapter basically tackles an animal and something about the sexuality of that animal. Do you have a favorite or one of your favorites that you could tell us about? © 2022 npr

Keyword: Sexual Behavior
Link ID: 28335 - Posted: 05.25.2022

By Azeen Ghorayshi Marcia Herman-Giddens first realized something was changing in young girls in the late 1980s, while she was serving as the director for the child abuse team at Duke University Medical Center in Durham, N.C. During evaluations of girls who had been abused, Dr. Herman-Giddens noticed that many of them had started developing breasts at ages as young as 6 or 7. “That did not seem right,” said Dr. Herman-Giddens, who is now an adjunct professor at the University of North Carolina Gillings School of Global Public Health. She wondered whether girls with early breast development were more likely to be sexually abused, but she could not find any data keeping track of puberty onset in girls in the United States. So she decided to collect it herself. A decade later, she published a study of more than 17,000 girls who underwent physical examinations at pediatricians’ offices across the country. The numbers revealed that, on average, girls in the mid-1990s had started to develop breasts — typically the first sign of puberty — around age 10, more than a year earlier than previously recorded. The decline was even more striking in Black girls, who had begun developing breasts, on average, at age 9. The medical community was shocked by the findings, and many were doubtful about a dramatic new trend spotted by an unknown physician assistant, Dr. Herman-Giddens recalled. “They were blindsided,” she said. But the study turned out to be a watershed in the medical understanding of puberty. Studies in the decades since have confirmed, in dozens of countries, that the age of puberty in girls has dropped by about three months per decade since the 1970s. A similar pattern, though less extreme, has been observed in boys. Although it is difficult to tease apart cause and effect, earlier puberty may have harmful impacts, especially for girls. Girls who go through puberty early are at a higher risk of depression, anxiety, substance abuse and other psychological problems, compared with peers who hit puberty later. Girls who get their periods earlier may also be at a higher risk of developing breast or uterine cancer in adulthood. © 2022 The New York Times Company

Keyword: Hormones & Behavior; Development of the Brain
Link ID: 28332 - Posted: 05.21.2022

By Natasha Gilbert In May of 2018, Tabitha Bird spent a memorable day with her eldest son at a comic book convention in London. Later that evening, after she made sure that her two younger kids were safely tucked up in bed, Bird gathered every sleeping tablet, antidepressant, anti-anxiety med and ibuprofen pill she could find and walked out of the house. She drove to a nearby store where she bought a big bottle of water and some acetaminophen. Then she stopped in an empty industrial park and began to take the lot. Bird woke up from a coma four days later. The 47-year-old, from a town in West Sussex in the UK, now attributes her suicide attempt and the depression leading up to it to perimenopause — the time in most women’s lives when menstrual cycles become irregular and fertility wanes. During this transition, many women experience a suite of changes, including hot flashes, disrupted sleep and mood swings. Some breeze through perimenopause with little difficulty, but many — about 45 percent to 68 percent — experience depression, symptoms of which can include low mood, a loss of interest in things and even thoughts of suicide. Women with a history of depression, like Bird — who also suffered with it while pregnant — are the most vulnerable. During perimenopause, they are twice as likely to experience debilitating full-blown depressive disorder than women who haven’t had past episodes. As researchers probe for reasons why some women fall prey to depression at this time and others don’t, a leading candidate has emerged: widely fluctuating levels of the sex hormone estrogen. Estrogen directs fertility, but mounting research shows that it also holds sway on parts of the brain involved in regulating emotion and stress. © 2022 Annual Reviews

Keyword: Depression; Hormones & Behavior
Link ID: 28329 - Posted: 05.18.2022

By Hope Reese Can we do without love? For many years, the neuroscientist Stephanie Ortigue believed that the answer was yes. Even though she researched the science of human connections, Dr. Ortigue — an only child and, in her 20s and 30s, contentedly single — couldn’t completely grasp its importance in her own life. “I told myself that being unattached made me a more objective researcher: I could investigate love without being under its spell,” she writes in her new book, “Wired for Love: A Neuroscientist’s Journey Through Romance, Loss and the Essence of Human Connection.” But then, in 2011, at age 37, she met John Cacioppo at a neuroscience conference in Shanghai. Dr. Cacioppo, who popularized the concept that prolonged loneliness can be as toxic to health as smoking, intrigued her. The two scientists fell hard for each other and married. She took his last name and they soon became colleagues at the University of Chicago’s Pritzker School of Medicine (where she now directs the Brain Dynamics Laboratory) — forming a team at home and in the lab. “Wired for Love” is the neurobiological story of how love rewires the brain. It’s also a personal love story — one that took a sad turn when John died of cancer in March 2018. Here, Dr. Cacioppo discusses what exactly love does to the brain, how to fight loneliness and how love is, literally, a product of the imagination. You went from being happily single, to coupled, to then losing your husband. How did meeting him bring your research on love to life? Sign Up for Love Letter Your weekly dose of real stories that examine the highs, lows and woes of relationships. This newsletter will include the best of Modern Love, weddings and love in the news. Get it sent to your inbox. When we first met, we spoke for three hours, but I couldn’t feel time go by. I felt euphoria — from the rush of dopamine. I blushed — a sign of adrenaline. We became closer, physically, and started imitating each other. This was from the activation of mirror neurons, a network of brain cells that are activated when you move or feel something, and when you see another person moving. When you have a strong connection with someone, the mirror neuron system is boosted. © 2022 The New York Times Company

Keyword: Sexual Behavior; Emotions
Link ID: 28302 - Posted: 04.27.2022

Carrie Arnold Playing the mating game is risky. Organisms must cope with the existential risk that swiping right on the wrong choice could doom future generations to a lifetime of bad genes. They also have to contend with more immediate burdens and risks: Participants need to gather resources for courting and summon energy to pursue a potential partner. Animals engaged in amorous activities also make easy targets for predators. Small wonder, then, that when times are good, the roundworm Caenorhabditis elegans doesn’t bother with the process. As a mostly hermaphroditic species (with a few males thrown in for variety), a C. elegans worm usually self-fertilizes its eggs until its sperm stash is depleted late in life; only then does it produce a pheromone to attract males and stay in the reproductive game. But when environmental conditions become stressful, the worms become sexually attractive much sooner. For them, sex is the equivalent of a Hail Mary pass — a desperate gamble that if their offspring are more genetically diverse, some will fare better under the new, rougher conditions. Scientists thought this stress-induced shift was purely fleeting. But recently when scientists at Tel Aviv University raised C. elegans in too-warm conditions for more than 10 generations, they discovered that the worms continued to be sexually attractive for several more generations after they were moved to cooler surroundings. It’s an observation that highlights how inheritance does not always reduce to a simple accounting of the genes in organisms, and it may point to a mechanism that works in tandem with traditional natural selection in shaping the evolution of some organisms. As the new paper in Developmental Cell shows, the cause of this trait wasn’t a genetic change to the worm’s DNA but rather an inherited “epigenetic” change that influenced how the DNA was used. The researchers — senior author Oded Rechavi, a biologist at Tel Aviv University, first author Itai Toker (now a postdoctoral fellow at Columbia University) and their colleagues — identified a small RNA molecule that can be passed between generations to signal for production of the pheromone. In effect, this heritable RNA molecule improves the odds that the worms will evolve in stressful times. All Rights Reserved © 2022

Keyword: Sexual Behavior; Epigenetics
Link ID: 28299 - Posted: 04.23.2022

By Gina Kolata Are you a man worried about your testosterone levels? Hoping to give them a boost? Tucker Carlson, the Fox News host, has a solution. A promotional video for a new installment in a video series by Mr. Carlson describes a “total collapse of testosterone levels in American men,” positing an explanation for what he and many conservatives see as a creeping loss of masculinity in today’s society. Chock-full of oiled, shirtless men performing vaguely masculine tasks, like turning over giant tires and throwing a javelin, the video has already been widely remarked upon on social media for its bizarre erotic imagery. But one shot in particular stands out: a naked man atop a rock pile, limbs outflung, exposing his genitals to the red light issuing from what appears to be a waist-high air purifier. Something very like the theme from “2001: A Space Odyssey” plays in the background. This is the treatment proposed by Mr. Carlson’s “documentary”: Revive your underperforming testicles with red light, in particular a device made by a little known company called Joovv. A leading endocrinologist says — no surprise — the whole thing is ridiculous, and not just because of the man receiving light therapy atop a pile of stone slabs in the dead of night. First, there is precious little evidence that testosterone “levels are declining by roughly 10 percent per decade, completely changing the way people are at the most fundamental level,” as Mr. Carlson has said. Studies examining changes in testosterone over time are challenging for several reasons, including difficulties in recruiting large populations of normal subjects, daily circadian changes in testosterone, and differences in testing methods over time, noted Dr. John Amory, an expert on male reproductive health at the University of Washington. © 2022 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 28298 - Posted: 04.23.2022

By Jake Buehler Earthen piles built by a chicken-like bird in Australia aren’t just egg incubators — they may also be crucial for the distribution of key nutrients throughout the ecosystem. In the dry woodlands of South Australia, sandy mounds rise between patches of many-stemmed “mallee” eucalyptus trees. These monuments — big enough to smother a parking space — are nests, painstakingly constructed by the malleefowl bird. By inadvertently engineering a patchwork of nutrients and churned soil, the industrious malleefowl may be molding surrounding plant and soil communities and even blunting the spread of fire, researchers report March 27 in the Journal of Ecology. Such ecosystem impacts suggest malleefowl conservation could benefit many species, says Heather Neilly, an ecologist at the Australian Landscape Trust in Calperum Station. The species is currently listed as “vulnerable” and declining by the International Union for Conservation of Nature. Some animals — termed “ecosystem engineers” — produce habitats for other species by shaping the environment around them. Beavers build dams that create homes for pond-dwelling lifeforms. In deserts, owls and giant lizards support plant and animal life with their burrows (SN: 10/8/19; SN: 1/19/21). “In Australia in particular, the focus has largely been on our array of digging mammals,” Neilly says. But malleefowl (Leipoa ocellata) — found throughout western and southern Australia — also perturb the soil. They and their close relatives are “megapodes,” a group of fowl native to Australasia and the South Pacific that have the unusual habit of incubating their eggs much like alligators do: in a massive pile of rotting compost. Heat from the decaying vegetation — locked in with an insulating sand layer on top — regulates the eggs’ temperature, and the young scratch their way to the surface upon hatching. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28280 - Posted: 04.13.2022

By Christina Caron Q: Are there any proven treatments for low libido in women? “Proven” is a strong word — and one that makes scientists squeamish. But it is safe to say that there is “very strong evidence” for increasing sexual desire through certain types of psychological interventions like cognitive behavioral therapy and mindfulness meditation, said Lori A. Brotto, a psychologist and professor at the University of British Columbia in Vancouver and a renowned expert in women’s sexual health. When it comes to medications, however, it’s a different story. In recent years, two new medications for women with low libido have been approved by the U.S. Food and Drug Administration, “though their efficacy is marginally better than a placebo,” said Dr. Stacy Tessler Lindau, a gynecologist at the University of Chicago Medicine and the creator of WomanLab, a website about sexual health. These drugs, flibanserin (a pill) and bremelanotide (an injection that is self-administered about 40 minutes before sexual activity), were approved for the “very small subset of women” who are premenopausal, have low libidos and do not have any identifiable physical, mental or relationship problems, Dr. Lindau said. “They may have modest benefit, but they also come with side effects and cost,” she added. “So far, insurance coverage has been limited.” In the end, the most beneficial solution will depend on the reason you are experiencing low libido and why you consider your libido to be a problem. For older women, loss of estrogen during menopause is commonly associated with a change in libido because it can cause vaginal dryness and tightness that can make intercourse painful. Some women also find it more difficult to get aroused. And when menopause is accompanied by hot flashes and night sweats, that can make sex seem less appealing too. © 2022 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28235 - Posted: 03.11.2022

Megan Lim Any parents out there will be familiar with the unique sort of misery that results when your kid has a new favorite song. They ask to hear it over and over, without regard for the rest of us. Well, it turns out that song sparrows might be better than children (and many adults, for that matter) when it comes to curating their playlists. Male sparrows, which attract females by singing, avoid tormenting their listeners with the same old tune. Instead they woo potential mates with a selection of 6 to 12 different songs. The song sparrow medley It might be hard to tell, but that audio clip contains three distinctive sparrow songs, each containing a unique signature of trills and notes. Even more impressive than the execution, though, is the way sparrows string their songs together. William Searcy, an ornithologist at the University of Miami, recently published a study in The Royal Society that analyzed patterns of song sparrow serenades. He said it would be easy for the birds to sing the first song, then the second, then the third and fourth. "But that's not what song sparrows are doing. They're not going through in a set order. They're varying the order from cycle to cycle, and that's more complicated," he said. In other words, rather than sing the same playlist every time, they hit shuffle. "What we're arguing is what they do is keep in memory the whole past cycle so they know what to sing next," Searcy said. The researchers are not sure why male sparrows shuffle their songs. But past work has shown that females prefer hearing a wider range of tunes, so maybe a new setlist keeps females interested. © 2022 npr

Keyword: Animal Communication; Sexual Behavior
Link ID: 28181 - Posted: 02.02.2022

By Azeen Ghorayshi An upsurge in teenagers requesting hormones or surgeries to better align their bodies with their gender identities has ignited a debate among doctors over when to provide these treatments. An international group of experts focused on transgender health last month released a draft of new guidelines, the gold standard of the field that informs what insurers will reimburse for care. Many doctors and activists praised the 350-page document, which was updated for the first time in nearly a decade, for including transgender people in its drafting and for removing language requiring adults to have psychological assessments before getting access to hormone therapy. But the guidelines take a more cautious stance on teens. A new chapter dedicated to adolescents says that they must undergo mental health assessments and must have questioned their gender identity for “several years” before receiving drugs or surgeries. Experts in transgender health are divided on these adolescent recommendations, reflecting a fraught debate over how to weigh conflicting risks for young people, who typically can’t give full legal consent until they are 18 and who may be in emotional distress or more vulnerable to peer influence than adults are. Some of the drug regimens bring long-term risks, such as irreversible fertility loss. And in some cases, thought to be quite rare, transgender people later “detransition” to the gender they were assigned at birth. Given these risks, as well as the increasing number of adolescents seeking these treatments, some clinicians say that teens need more psychological assessment than adults do. “They absolutely have to be treated differently,” said Laura Edwards-Leeper, a child clinical psychologist in Beaverton, Ore., who works with transgender adolescents. Dr. Edwards-Leeper was one of seven authors of the new adolescent chapter, but the organization that publishes the guidelines, the World Professional Association for Transgender Health, did not authorize her to comment publicly on the draft’s proposed wording. © 2022 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28156 - Posted: 01.15.2022