Chapter 12. Sex: Evolutionary, Hormonal, and Neural Bases

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By Leigh Weingus I’ve struggled with sleep since I was a teenager, and have spent almost as long trying to fix it. I’ve absorbed countless books and articles on getting better sleep that instructed me to go blue-light free at least two hours before bedtime, take nightly baths to lower my body temperature, keep my phone far from my bedroom and avoid caffeine after 12 p.m. In between all my diligent sleep hygiene work, I couldn’t help but feel like there was a larger force at play. My sleep seemed to change throughout my menstrual cycle, for example, getting worse in the days before my period and significantly better afterward. When I was pregnant, I experienced the best sleep of my life, and when I stopped breastfeeding, I didn’t sleep for days. I finally started to ask myself: When we talk about getting better sleep, why aren’t we talking more about hormones? According to the National Sleep Foundation, the lifetime risk of insomnia is 40 percent higher for women than it is for men. Blaming this discrepancy entirely on hormones oversimplifies it — women also tend to take on the bulk of household worrying and emotional labor, and they tend to experience higher levels of anxiety. But according to Mary Jane Minkin, an obstetrician-gynecologist and clinical professor in the Department of Obstetrics, Gynecology, and Reproductive Sciences at the Yale School of Medicine, anecdotal evidence and studies suggest that hormones likely play a role.

Keyword: Sleep; Hormones & Behavior
Link ID: 28000 - Posted: 09.22.2021

By Joshua Rapp Learn Giraffes don’t fight much, says Jessica Granweiler, a master’s student at the University of Manchester in England who studies nature’s tallest mammals. When they do, look out. “Fighting is extremely rare because it’s extremely violent,” Ms. Granweiler said. When older adult males joust for territory or mating rights, their hornlike pairs of ossicones thrust with the force of their long necks and can cut into their opponents’ flesh, wounding and sometimes even killing a combatant. But some forms of giraffe dueling serve other purposes. In a study published last month in the journal Ethology, Ms. Granweiler and her colleagues reported some discoveries about sparring behavior that help giraffes establish social hierarchies. They showed that the animals didn’t take advantage of smaller members of their herds, but rather practiced their head butts with males of similar stature in ways that to a human might even appear fair or honorable. Such findings could aid in the conservation of the dwindling populations of the animals. Ms. Granweiler and her colleagues observed social behavior in giraffes at the small Mogalakwena River Reserve in South Africa from November 2016 to May 2017. They began to record the details of these fights — basically a who-fought-who, and how in the giraffe world. They were surprised to find that giraffes, like humans, can be righties or southpaws when it comes to sparring. Even the youngest animals showed a clear preference, although unlike humans it seemed they were evenly split between lefties and righties. The researchers also noticed that the younger males sparred more with each other, and nearly always chose opponents similar in size to themselves — there wasn’t a lot of bullying going on. A bar brawl effect went on as well, where one sparring match seemed to infect the crowd and prompt more fights around them. © 2021 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 27997 - Posted: 09.18.2021

by Rachel Zamzow The X chromosome holds stronger-than-expected genetic sway over the structure of several brain regions, a new study finds. The X-linked genes that may underlie this oversized influence have ties to autism and intellectual disability. “There were already hints that the X chromosome was likely to be conspicuous, with how involved it is with the brain,” says lead investigator Armin Raznahan, chief of the section on developmental neurogenomics at the U.S. National Institute of Mental Health. Many X chromosome genes — including those at the root of several autism-related conditions, such as fragile X syndrome and Rett syndrome — are expressed in the brain, for example. But the new findings suggest that the X chromosome, despite containing only 5 percent of the human genome, has a privileged role in shaping the brain — one that may be particularly relevant to developmental conditions. What’s more, this influence may be stronger in men than in women, the study shows. “What they’re showing is X is fundamentally different,” says David Glahn, professor of psychology at Harvard University, who was not involved in the new study. “It’s off the scale.” Research over the past decade has linked genetic variation to shifts in brain features, such as overall size or patterns of connectivity between regions, Glahn says. But “the X chromosome and the Y chromosome are fundamentally understudied,” because including them requires extra analytical legwork, he says. © 2021 Simons Foundation

Keyword: Development of the Brain; Genes & Behavior
Link ID: 27992 - Posted: 09.15.2021

Nicola Davis Premature babies appear to feel less pain during medical procedures when they are spoken to by their mothers, researchers have found. Babies that are born very early often have to spend time in neonatal intensive care units, and may need several painful clinical procedures. The situation can also mean lengthy separation from parents. Now researchers say they have found the sound of a mother’s voice seems to decrease the pain experienced by their baby during medical procedures. Dr Manuela Filippa, of the University of Geneva and first author of the study, said the research might not only help parents, by highlighting that they can play an important role while their baby is in intensive care, but also benefit the infants. Advertisement Last man out: the haunting image of America’s final moments in Afghanistan “We are trying to find non-pharmacological ways to lower the pain in these babies,” she said, adding that there was a growing body of evidence that parental contact with preterm babies could be important for a number of reasons, including attachment. Filippa said the team focused on voice because it was not always possible for parents to hold their babies in intensive care, while voice could be a powerful tool to share emotion. Mothers’ voices were studied in particular because infants would already have heard it in the womb. But Filippa said that did not mean a father’s voice could not become as familiar over time. “We are [also] running studies on fathers’ vocal contacts,” she said. Writing in the journal Scientific Reports, Filippa and colleagues at the University of Geneva, Parini hospital in Italy and the University of Valle d’Aosta, report how they examined the pain responses of 20 premature babies in neonatal intensive care to a routine procedure in which the foot is pricked and a few drops of blood collected. © 2021 Guardian News & Media Limited

Keyword: Pain & Touch; Development of the Brain
Link ID: 27973 - Posted: 09.01.2021

By Carolyn Wilke Some female hummingbirds don flashy feathers to avoid being bothered by other hummingbirds, a new study suggests. Male white-necked jacobin hummingbirds (Florisuga mellivora) have bright blue heads and throats. Females tend to have more drab hues, but some sport the blue coloring too. Appearing fit and fine to impress potential mates can often explain animals’ vibrant colors. But mate choice doesn’t seem to drive these females’ pretty plumage since males don’t appear to prefer the blue females. Instead, bright colors may help lady birds blend in with the guys, and as a result, feed for longer without harassment from other hummingbirds, researchers report August 26 in Current Biology. Beyond vying for mates, animals often also compete for territory, parental attention, social ranks and food (SN: 4/7/16). Mating choices don’t capture all those other interactions and can’t always explain animals’ looks, says Jay Falk, an evolutionary biologist at the University of Washington in Seattle. To begin investigating why some female jacobins have colorful blue plumage, Falk and colleagues captured and released over 400 of the birds in Gamboa, Panama, using genetics to determine their sex. Most females had drab colors — olive green heads and backs and mottled throats. But nearly 30 percent of females had the shimmery blue noggins that all juveniles have and that are characteristic of adult males. © Society for Science & the Public 2000–2021.

Keyword: Sexual Behavior; Evolution
Link ID: 27969 - Posted: 08.28.2021

By Teresa Carr In the fall of 2016, sex therapist and researcher Leonore Tiefer shuttered the New View Campaign, an organization she had founded to combat what she refers to as “the medicalization of sex” — essentially, the pharmaceutical industry’s efforts to define variations in sexuality and sexual problems as medical issues requiring a drug fix. For 16 years, the group had fought against industry’s involvement in sex research, including its push for a drug to boost women’s sex drives. New View hosted conferences and its members penned papers and testified before the United States Food and Drug Administration. The campaign was prominently featured in an 80-minute documentary called Orgasm Inc, and promoted a clever (if off-pitch) video advising women to “throw that pink pill away,” a reference to the female-libido drug flibanserin (Addyi), which was seeking FDA approval at the time. New View counted some successes: The FDA didn’t approve an allegedly libido-boosting testosterone patch for women, on the grounds that the patch’s slim benefits didn’t outweigh its risks, and the FDA twice rejected flibanserin for the same reason. But in August 2015, the agency reversed itself and approved the so-called pink Viagra. “I felt we’d said everything we had to say,” said Tiefer of ending the campaign. Advocates predicted FDA approval would be sought for additional women’s libido drugs, but the group felt there was nothing they could do to stop it. “However many more drugs were going to come down the pike,” said Tiefer, “it was just going to be more of the same.”

Keyword: Sexual Behavior
Link ID: 27948 - Posted: 08.14.2021

Jake Buehler As the midday sun hangs over the Scandinavian spruce forest, a swarm of hopeful suitors takes to the air. They are dance flies, and it is time to attract a mate. Zigzagging and twirling, the flies show off their wide, darkened wings and feathery leg scales. They inflate their abdomens like balloons, making themselves look bigger and more appealing to a potential partner. Suddenly, the swarm electrifies with excitement at the arrival of a new fly, the one they have all been waiting for: a male. It’s time for the preening flock of females to shine. The flies are flipping the classic drama reenacted across the animal kingdom, in which eager males with dazzling plumage, snarls of antlers or other extraordinary traits compete for a chance to woo a reluctant female. Such competitions between males for the favor of choosy females are enshrined in evolutionary theory as “sexual selection,” with the females’ choices molding the evolution of the males’ instruments of seduction over generations. Yet it’s becoming clear that this traditional picture of sexual selection is woefully incomplete. Dramatic and obvious reversals of the selection scenario, like that of the dance flies, aren’t often observed in nature, but recent research suggests that throughout the tree of animal life, females jockey for the attention of males far more than was believed. A new study hosted on the preprint server biorxiv.org has found that in animals as diverse as sea urchins and salamanders, females are subject to sexual selection — not as harshly as males are, but enough to make biologists rethink the balance of evolutionary forces shaping species in their accounts of the history of life. All Rights Reserved © 2021

Keyword: Sexual Behavior; Evolution
Link ID: 27934 - Posted: 08.07.2021

Katharine Sanderson Liz Williams was standing pitchside at a women’s rugby match, and she did not like what she was seeing. Williams, who researches forensic biomechanics at Swansea University, UK, had equipped some of the players with a mouthguard that contained a sensor to measure the speed of head movement. She wanted to understand more about head injuries in the brutal sport. “There were a few instances when my blood went cold,” Williams said. When the women fell in a tackle, their heads would often whiplash into the ground. The sensors showed that the skull was accelerating — indicating an increased risk of brain injury. But medical staff at the match, not trained to look out for this type of head movement as a cause of injury, deemed the women fine to play on. Such whiplash injuries are much rarer when males play. Williams’ observations highlight an increasingly apparent problem. A growing body of data suggests that female athletes are at significantly greater risk of a traumatic brain injury event than male athletes. They also fare worse after a concussion and take longer to recover. As researchers gather more data, the picture becomes steadily more alarming. Female athletes are speaking out about their own experiences, including Sue Lopez, the United Kingdom’s first semi-professional female football player in the 1970s, who now has dementia — a diagnosis she has linked to concussions from heading the ball. Researchers have offered some explanations for the greater risk to women, although the science is at an early stage. Their ideas range from differences in the microstructure of the brain to the influence of hormones, coaching regimes, players’ level of experience and the management of injuries. © 2021 Springer Nature Limited

Keyword: Brain Injury/Concussion; Sexual Behavior
Link ID: 27932 - Posted: 08.04.2021

By Kim Tingley During menopause, which marks the end of a woman’s menstrual cycles, her ovaries stop producing the hormones estrogen and progesterone, bringing an end to her natural childbearing years. But those hormones also regulate how the brain functions, and the brain governs their release — meaning that menopause is a neurological process as well. “Many of the symptoms of menopause cannot possibly be directly produced by the ovaries, if you think about the hot flashes, the night sweats, the anxiety, the depression, the insomnia, the brain fog,” says Lisa Mosconi, an associate professor of neurology at Weill Cornell Medicine and director of its Women’s Brain Initiative. “Those are brain symptoms, and we should look at the brain as something that is impacted by menopause at least as much as your ovaries are.” In June, Mosconi and her colleagues published in the journal Scientific Reports one of the few studies to observe in detail what happens to the brain throughout the menopause transition, not just before and after. Using various neuroimaging techniques, they scanned the brains of more than 160 women between the ages of 40 and 65 who were in different stages of the transition to examine the organ’s structure, blood flow, metabolism and function; they did many of the same scans two years later. They also imaged the brains of men in the same age range. “What we found in women and not in men is that the brain changes quite a lot,” Mosconi says. “The transition of menopause really leads to a whole remodeling.” On average, women in the United States enter the menopause transition — defined as the first 12 consecutive months without a period — at around 50; once diagnosed, they are in postmenopause. But they may begin to have hormonal fluctuations in their 40s. (For some women, this happens in their 30s, and surgical removal of the ovaries causes immediate menopause, as do some cancer treatments.) Those fluctuations cause irregular periods and potentially a wide variety of symptoms, including hot flashes, insomnia, mood swings, trouble concentrating and changes in sexual arousal. During this phase, known as perimenopause, which averages four years in length (but can last from several months to a decade), Mosconi and colleagues observed that their female subjects experienced a loss of both gray matter (the brain cells that process information) and white matter (the fibers that connect those cells). Postmenopause, however, that loss stopped, and in some cases brain volume increased, though not to its premenopausal size. © 2021 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 27917 - Posted: 07.21.2021

By Elizabeth Pennisi In hyenas as well as humans, it pays to be born to high-ranking parents. A new study reveals how power is passed down in these matriarchal mammals: Elite hyena cubs cultivate their mom’s friends, who help keep them fed and protected throughout their lives. The work drives home the role moms and dads play in shaping the social world of their children, says Josh Firth, a social networks researcher at the University of Oxford who was not involved with the study. “We tend to think about who we are connected to as a product of our doing, but it’s a product of our parents as well.” Chimpanzees, hyenas, and other social animals live in hierarchical societies. Those at the top eat first, and are typically surrounded by a gang that protects them from other members of their species that try to challenge their status. High rank tends to be inherited, but it’s been unclear how subsequent generations end up with the same type of ruling clan their parents do. Do they recruit their own powerful allies, or inherit them? Erol Akçay, a theoretical biologist at the University of Pennsylvania, and behavioral ecologist Amiyaal Ilany, now at Bar-Ilan University, decided to analyze the work of Kay Holekamp. A behavioral ecologist at Michigan State University, Holekamp’s team had been following the lives of a clan of spotted hyenas (Crocuta crocuta) in Kenya for almost 30 years. Day after day, the researchers have recorded the activity of the hyenas, including their interactions with and proximity to other hyenas, to understand the species’ behavior and ecology. They have also kept track of the pedigrees and social status of each female and its offspring. © 2021 American Association for the Advancement of Science.

Keyword: Aggression; Sexual Behavior
Link ID: 27912 - Posted: 07.17.2021

By Marlene Cimons J. William Langston, who has been studying and treating Parkinson’s disease for nearly 40 years, always has found it striking that so many more men than women show up in his clinic. His observation is not anecdotal. It is grounded in science and shared by many physicians: Men are roughly 1.5 times more likely than women to develop Parkinson’s, a progressive disorder of the nervous system that impairs movement and can erode mental acuity. “It’s a big difference that is quite real,” says Langston, clinical professor of neurology, neuroscience and of pathology at the Stanford University School of Medicine and associate director of the Stanford Udall Center. “It’s pretty dramatic. I think anyone who sees a lot of Parkinson’s will tell you that.” While the disproportionate impact is clear, the reasons for it are not. “It’s a great mystery,” Langston says. Researchers still don’t know what it is that makes men more susceptible to Parkinson’s, or what it is about women that may protect them — or both. But they are trying to find out. “We in the research community have been working for decades to sort this out, but the answers are still elusive,” says Caroline Tanner, a neurology professor in the Weill Institute for Neurosciences at the University of California at San Francisco. “Nevertheless, it’s important to keep at it. We need to understand the mechanisms that underlie the specific differences between men and women so we can apply them to trying to prevent Parkinson’s.” Parkinson’s results from the death of key neurons in the substantia nigra region of the brain that produce the chemical messenger dopamine. Over time, the loss of these nerve cells disrupts movement, diminishes cognition, and can cause other symptoms, such as slurred speech and depression. © 1996-2021 The Washington Post

Keyword: Parkinsons; Sexual Behavior
Link ID: 27892 - Posted: 07.06.2021

Rebecca Brooker & Tristin Nyman Even before the pandemic, there was plenty for expectant mothers to worry about. Pregnant women must withstand a barrage of arguably well-intentioned, but often hyperbolic, warnings about their health and what’s to come, including concerns about everything from what to eat, to what to wear, to how to feel. Health professionals know that mothers-to-be experience predictable increases in anxiety levels before infants are born. Maternal mental health has been steadily deteriorating in the U.S., particularly among poor and minority women. The calls to “be afraid, be very afraid” are, of course, countered by the equally strong cautions for pregnant women to not worry too much, lest it lead to long-term negative outcomes for them and their infants. Such warnings are not entirely off base. Maternal stress hormones cross the placenta and affect the vulnerable fetus. Fetal exposure to the stress hormone cortisol has been linked to an array of negative outcomes, including miscarriage and preterm birth, and irritable temperament for the child and increased risk of emotional problems during childhood. One thing researchers know is that anxious mothers tend to have anxious children. This common, albeit not prescriptive, phenomenon is likely due to numerous factors, both pre- and postpartum. In our laboratory, we focus on what happens when women start their pregnancies already worried or anxious and what clues we can uncover about how to help them and their children. Our research suggests that worry during pregnancy can have long-term impacts on how mothers’ brains communicate – but also that there might be some simple steps that can help rein in the effects. © 2010–2021, The Conversation US, Inc.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 27820 - Posted: 05.15.2021

by Jessica Jiménez, Mark Zylka Mice and rats typically give birth to 6 to 12 animals per litter. Some scientists treat this as a benefit, because a large number of animals can be produced with a small number of matings. In reality, though, this is of no benefit at all, especially when you consider a fact that is well known in the toxicology field: Animals within a litter are more similar to one another than animals between litters. Herein lies what is known as the ‘litter effect.’ Anyone who uses multiple animals from a small number of litters to increase sample size is making a serious mistake. The similarities within individual litters will heavily skew the results. Our goal in writing this article, and an accompanying peer-reviewed paper on this topic, is to raise awareness about the litter effect and to encourage researchers who study neurodevelopmental conditions to control for it in future work. Like many scientists who use rodents to study autism and related conditions, we were oblivious to the litter effect and its impact on research. However, we now recognize that it is essential to control for the litter effect whenever a rodent autism model is studied, be it a mouse with a gene mutation or an environmental exposure. It is essential because the litter effect can lead to erroneous conclusions that negatively influence the rigor and reproducibility of scientific research. Indeed, false positives, or the incorrect identification of a significant effect, increase as fewer litters are sampled. Conversely, litter-to-litter variation adds ‘noise’ to the data that can mask true treatment or genetic effects. This is concerning because most phenotypes associated with rodent models of autism are remarkably small, and they are often difficult to reproduce between labs. © 2021 Simons Foundation

Keyword: Development of the Brain; Sexual Behavior
Link ID: 27789 - Posted: 04.28.2021

Lise Eliot Everyone knows the difference between male and female brains. One is chatty and a little nervous, but never forgets and takes good care of others. The other is calmer, albeit more impulsive, but can tune out gossip to get the job done. These are stereotypes, of course, but they hold surprising sway over the way actual brain science is designed and interpreted. Since the dawn of MRI, neuroscientists have worked ceaselessly to find differences between men’s and women’s brains. This research attracts lots of attention because it’s just so easy to try to link any particular brain finding to some gender difference in behavior. But as a neuroscientist long experienced in the field, I recently completed a painstaking analysis of 30 years of research on human brain sex differences. And what I found, with the help of excellent collaborators, is that virtually none of these claims has proven reliable. Except for the simple difference in size, there are no meaningful differences between men’s and women’s brain structure or activity that hold up across diverse populations. Nor do any of the alleged brain differences actually explain the familiar but modest differences in personality and abilities between men and women. © 2010–2021, The Conversation US, Inc.

Keyword: Sexual Behavior; Brain imaging
Link ID: 27784 - Posted: 04.24.2021

By Emily Anthes Male tanagers are meant to be noticed. Many species of the small, tropical bird sport deep black feathers and splashes of eye-catching color — electric yellows, traffic-cone oranges and nearly neon scarlets. To achieve this flashiness, the birds must spend time and energy foraging for, and metabolizing, plants that contain special color pigments, which make their way into the feathers. A vibrantly colored male is thus sending an “honest signal,” many scientists have long theorized: He is alerting nearby females that he has a good diet, is in good health and would make a worthy mate. But some birds may be guilty of false advertising, a new study suggests. Male tanagers have microstructures in their feathers that enhance their colors, researchers reported Wednesday in the journal Scientific Reports. These microstructures, like evolution’s own Instagram filters, may make the males seem as if they are more attractive than they truly are. “Many male birds are colorful not just because they’re honestly signaling their quality, but because they’re trying to get chosen,” said Dakota McCoy, a doctoral student at Harvard University who conducted the research as part of her dissertation. “This is basically experimental evidence that whenever there’s a high-stakes test in life, it’s worth your while to cheat a little bit.” The new study is an important contribution to the longstanding debate over how, and why, brightly colored feathers evolved in birds, said Geoffrey Hill, an ornithologist and evolutionary ecologist at Auburn University. “Scientists have spent the last 150 years since Darwin and Wallace trying to understand ornaments in animals and especially colors in birds,” he said. “And this is the kind of original approach that helps us.” © 2021 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 27781 - Posted: 04.21.2021

Nicola Davis It is a trope used in films from King Kong to Tarzan – a male primate standing upright and beating its chest, sometimes with a yell and often with more than a dash of hubris. But it seems the pounding action is less about misplaced bravado than Hollywood would suggest: researchers studying adult male mountain gorillas say that while chest-beating might be done to show off, it also provides honest information. “We found it is definitely a real, reliable signal – males are conveying their true size,” said Edward Wright, co-author of the research from the Max Planck Institute for Evolutionary Anthropology in Germany. Advertisement Writing in the journal Scientific Reports, Wright and colleagues report how they studied chest-beating in six adult male mountain gorillas in the Volcanoes national park in Rwanda. The team used a camera setup involving two parallel green lasers a known distance apart to determine the breadth of each gorilla’s back from a photograph. They then recorded 36 chest-beating episodes among these six males between November 2015 and July 2016, and analysed the recordings. The results revealed that the duration of the chest-beating, number of beats and the rate of the beats during an episode were not associated with the size of the gorilla. However, the average peak frequency of the sound produced was – the larger the gorilla, the lower the frequency of the sound produced. © 2021 Guardian News & Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 27765 - Posted: 04.10.2021

By Jake Buehler Fairy wrasses are swimming jewels, flitting and flouncing about coral reefs. The finger-length fishes’ brash, vibrant courtship displays are meant for mates and rivals, and a new study suggests that the slow waxing and waning of ice sheets and glaciers may be partly responsible for such a variety of performances. A new genetic analysis of more than three dozen fairy wrasse species details the roughly 12 million years of evolution that produced their vast assortment of shapes, colors and behaviors. And the timing of these transformations implies that the more than 60 species of fairy wrasses may owe their great diversity to cyclic sea level changes over the last few millions of years, scientists report February 23 in Systematic Biology. Within the dizzying assembly of colorful reef fishes, fairy wrasses (Cirrhilabrus) can’t help but stand out. They are the most species-rich genus in the second most species-rich fish family in the ocean, says Yi-Kai Tea, an ichthyologist at the University of Sydney. “That is quite a bit of biodiversity,” says Tea, who notes that new fairy wrasse species are identified every year. Despite this taxonomic footprint, Tea says, scientists knew “next to nothing” about the fairy wrasses’ evolutionary history or why there were so many species. © Society for Science & the Public 2000–2021.

Keyword: Sexual Behavior; Evolution
Link ID: 27755 - Posted: 04.03.2021

By Alyson Krueger Samantha LaLiberte, a social worker in Nashville, thought she had made a full recovery from Covid-19. But in mid-November, about seven months after she’d been sick, a takeout order smelled so foul that she threw it away. When she stopped by the house of a friend who was cooking, she ran outside and vomited on the front lawn. “I stopped going places, even to my mom’s house or to dinner with friends, because anything from food to candles smelled so terrible,” Ms. LaLiberte, 35, said. “My relationships are strained.” She is dealing with parosmia, a distortion of smell such that previously enjoyable aromas — like that of fresh coffee or a romantic partner — may become unpleasant and even intolerable. Along with anosmia, or diminished sense of smell, it is a symptom that has lingered with some people who have recovered from Covid-19. The exact number of people experiencing parosmia is unknown. One recent review found that 47 percent of people with Covid-19 had smell and taste changes; of those, about half reported developing parosmia. “That means that a rose might smell like feces,” said Dr. Richard Doty, director of the Smell and Taste Center at the University of Pennsylvania. He noted that people typically recover their smell within months. Right now, Ms. LaLiberte can’t stand the scent of her own body. Showering is no help; the smell of her body wash, conditioner and shampoo made her sick. What’s more, she detected the same odor on her husband of eight years. “There is not a whole lot of intimacy right now,” she said. “And it’s not because we don’t want to.” “It’s a much bigger issue than people give it credit for,” said Dr. Duika Burges Watson, who leads the Altered Eating Research Network at Newcastle University in England and submitted a journal research paper on the topic. “It is something affecting your relationship with yourself, with others, your social life, your intimate relationships.” © 2021 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 27742 - Posted: 03.23.2021

Tinbete Ermyas & Kira Wakeam Roughly 35 bills are being proposed that would limit or prohibit transgender women from competing in women's athletics. Above, athletes run in the Women's 400 meter final during the Rio 2016 Olympic Games. Shaun Botterill/Shaun Botterill/Getty Images Throughout the country, roughly 35 bills have been introduced by state legislators that would limit or prohibit transgender women from competing in women's athletics, according to the LGBTQ rights group Freedom for All Americans. That's up from only two in 2019. The latest action in this push came last week, when Mississippi Governor Tate Reeves signed into law the "Mississippi Fairness Act." The law prohibits schools from allowing transgender female students to compete in female sports and cites "inherent differences between men and women" as one of the reasons to block these athletes from competition. The often heated debates around these bills have centered on whether transgender women and girls have an unfair advantage over cisgender women — a term used for those who identify with the sex assigned to them at birth. Proponents say the legislation is needed in order to maintain fairness in women's athletics by reducing what they believe is an inherent competitive edge of trans athletes who identify as female. Critics call that a false argument and say the proposals are being used as a way to discriminate against transgender Americans. These proposals, they say, also risk opening the door to humiliating treatment of women and girls who don't fit culturally-accepted notions of femininity. Often missing from the culture-war aspect of the debate is a focus on the type of questions that Dr. Eric Vilain has spent much of his career researching. Vilain, a pediatrician and geneticist who studies sex differences in athletes, says there are no good faith reasons to limit transgender women's participation in sports, especially at the high school level. Vilain has advised both the International Olympic Committee and the NCAA, and says these laws generally aren't based in scientific evidence, but rather "target women who have either a different biology or ... simply look different." © 2021 npr

Keyword: Sexual Behavior
Link ID: 27739 - Posted: 03.23.2021

Amanda Heidt In 2015, the National Institute of Neurological Disorders and Stroke released a report stating that more than 600 neurological conditions—including Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, and motor neuron disease, among others—affect an estimated 50 million Americans, a number that is growing each year. Many of these diseases share a common feature in the degradation of the blood-brain barrier (BBB), the cloak of endothelial cells that disposes of the brain’s waste while also providing necessary nutrients. To better understand these diseases and to develop new ways to treat them, scientists rely on increasingly sophisticated cellular models that attempt to mimic the full complexity of the BBB. The advent of hydrogels, microfluidics, and so-called organs on a chip all rely on stable cell lines to build a useful proxy, but new research suggests that all cells may not respond equally to experimentation. The Scientist spoke with Alisa Morss Clyne and Callie Weber, two bioengineers at the University of Maryland whose recent review, published March 16 in APL Bioengineering, makes the case for the inclusion of sex as a biological variable in cell-based experiments. Men and women, a growing body of evidence shows, respond differently to brain diseases in ways that can profoundly influence a study’s findings. Men, for example, are 1.5 times more likely to be diagnosed with Parkinson’s disease and often experience the condition more severely, perhaps because the higher levels of estrogen in premenopausal women shield the BBB from damage. When purchasing cells, Clyne says, scientists are rarely aware of the sex of the original cell donor, but it may ultimately have important consequences for the study of diseases, neurological or otherwise. © 1986–2021 The Scientist

Keyword: Sexual Behavior
Link ID: 27738 - Posted: 03.23.2021