sex

Female sex hormones play a vital role in defense against sexually transmitted diseases

Two McMaster University studies, to be published in the Journal of Virology, show that sex hormones have a profound effect on susceptibility of female mice to the herpes simplex virus, type 2 (HSV-2 ), one of the most common sexually transmitted diseases. Charu Kaushic, assistant professor and supervisor of the studies, says the implication of this work is quite significant. "The research...

Sexual cooperation: Mating increases longevity in ant queens

The phenomenon of sexual conflict is a powerful driving force in the evolution of reproductive biology for many animal species. Males often try to manipulate their female mates during copulation--for example, by traumatic inseminations (as in the case of bed bugs) or by the transfer of toxic seminal fluids (as in the case of the fruitfly Drosophila). These manipulations are beneficial to males be...

Variation in women's X chromosomes may explain differences among individuals, between sexes

The first comprehensive survey of gene activity in the X chromosomes of women has revealed an unexpected level of variation among individuals, according to new work by researchers at the Duke University Institute for Genome Sciences & Policy (IGSP) and Pennsylvania State University. The results may have important implications for understanding the differences in traits among women and...

Love's all in the brain: fMRI study shows strong, lateralized reward, not sex, drive

You just can't tell where you might find love these days. A team led by a neuroscientist, an anthropologist and a social psychologist found love-related neurophysiological systems inside a magnetic resonance imaging machine. They detected quantifiable love responses in the brains of 17 young men and women who each described themselves as being newly and madly in love. The multidisciplinary...

Same-Sex Mating Discovered in a Toxic Fungus

An infectious fungus has been found to defy the most basic tenet of sexual reproduction ?that successful mating requires individuals of the opposite sex, according to Howard Hughes Medical Institute researchers at Duke University Medical Center. In the April 21, 2005, issue of Nature, the researchers reported that, in the infectious fungus Cryptococcus neoformans, members of the same "sex"...

To sea or not to sea: When it comes to salmon sex, size sometimes doesn't matter

The ones that stay and the ones that stray are biological puzzles among Pacific salmon, of whom the vast majority ?but not all ?travel thousands of miles to sea and back to the streams where they hatched. There are chinook salmon populations in Idaho in which an occasional male stays put and matures when only 6 inches long ?that is, he's able to fertilize eggs at even that diminutive size,...

Radio-tracking associated with 'dramatic shift' in water vole sex ratio

Wildlife researchers are being warned that radio-tracking could be affecting the animals they are studying. According to new research published today in the British Ecological Society's Journal of Applied Ecology, fitting radio-collars to water voles was associated with a "dramatic shift" in the sex ratio of the animals' offspring, casting doubt on the assumption that radio-tracking does not fund...

New study: Sexually transmitted disease treatment can be effectively administered by sex partners

Effective control of sexually transmitted diseases (STDs) requires treatment of the sexual partners of infected patients. A new study shows that providing infected men with antibiotics to give their partners is more effective than traditional means of contacting and treating the partners, according to an article in the Sept. 1 issue of Clinical Infectious Diseases, now available online. Men with...

High rates of sexually transmitted infections found in young drug users

Researchers at the Johns Hopkins Bloomberg School of Public Health and other institutions found high rates of herpes simplex virus 2 and syphilis among young drug users in Baltimore, Md. The study found that women had significantly higher rates compared to their male counterparts, but did not find significant differences between injection drug users and non-injection drug users. Few of the infect...

Why were the HIV prevention trials in commercial sex workers abandoned?

One promising approach to help stem the global HIV epidemic is to give commercial sex workers an HIV medication (such as the drug tenofovir) before they have high risk sex in the hope of reducing their chances of becoming infected, an approach called "pre-exposure prophylaxis" (PREP). But activist groups, including Act Up-Paris have "halted the progress of at least two important clinical trials o...

Geckos: It's not always about sex

Usually when you give up something, there's a price to pay. Not so in the case of the Australian Bynoe's gecko. This line of all-female geckos doesn't need sex or a male to reproduce and, contrary to expectations, these "Wonder Woman" geckos can run farther and faster than their sexually reproducing relatives. The research findings are published in the journal Physiological and Biochemical Zoolog...

Secret sex life of killer fungus?

Aspergillus fumigatus is a medically important fungus, causing potentially life-threatening infections in patients with weakened immune systems. It is also a major cause of respiratory allergy, and it is implicated in asthma as well. The fungus has always been thought to lack the ability to reproduce sexually, but new discoveries by a multinational group of scientists indicate that the fungus has...

Hanging baskets of sex and death help fruit growers

A hanging basket style device is at the heart of a plan by researchers at the University of Warwick to harness the sex drive of a major pest of fruit orchards as a weapon to spread a virus to kill that very same pest. The device allows growers to selectively target the pest with a virus that kills its larvae without killing other beneficial insects. The researchers at Warwick HRI, th...

Single gene is genetic switch for fly sexual behavior

A male fly's sexual courtship of a female fly is a complicated business of tapping, singing, wing vibration, and licking, but a single gene is all that is needed to produce this complex behavior, according to new research published in this week's issue of the journal Cell. The gene encodes the Fruitless protein. Male and female flies carry different versions of the fruitless protein, as a...

MBL researchers probe how an ancient microbe thrives and evolves without sex

A January 2004 finding by biologists at the Josephine Bay Paul Center for Comparative Molecular Biology and Evolution added important evidence to the radical conclusion that a group of diminutive aquatic animals called bdelloid rotifers have evolved for tens of millions of years without sexual reproduction, in apparent violation of the rule that abandonment of sexual reproduction is a biological...

Same-sex mating by fungi spawned infection outbreak, evidence suggests

Same-sex mating between two less harmful yeast strains might have spawned an outbreak of disease among otherwise healthy people and animals on Vancouver Island, British Columbia, Howard Hughes Medical Institute geneticists at Duke University Medical Center have reported. The fungus, Cryptococcus gattii, is normally restricted to the tropics and subtropics. The researchers said their findin...

New GM mosquito sexing technique is step towards malaria control, report scientists

Scientists have genetically modified male mosquitoes to express a glowing protein in their gonads, in an advance that allows them to separate the different sexes quickly. Research published online today in Nature...

MUHC investigators search for the root of sexual pain in women

A multidisciplinary team consisting of researchers from McGill/MUHC and the CHUM have been awarded a grant of nearly $700,000 by the Canadian Institutes of Health Research (CIHR) to continue their groundbreaking research on pain suffered by some women during sexual intercourse. The new funding will allow the team, consisting of psychologists, gynecologists, physical therapists and statistician/ep...

Ocean 'dead zones' trigger sex changes in fish, posing extinction threat

Oxygen depletion in the world’s oceans, primarily caused by agricultural run-off and pollution, could spark the development of far more male fish than female, thereby threatening some species with extinction, according to a study published today on the Web site of the American Chemical Society journal, . The study is scheduled to appear in the May 1...

Sexual reproduction delays aging in a mammalian species

Past research on aging and the life histories of diverse species has shown that sexual reproduction is biologically costly for individuals and tends to decrease lifespan rather than increase it. But a new study by Philip Dammann and Hynek Burda from the University of Duisburg-Essen shows that, in a vertebrate species, the opposite can be true as well. The authors, studying captive Zambian...

Study: Competition for sex is a 'jungle out there'

Mother Nature could use a few more good pollinators, especially in species-rich biodiversity hotspots, according to a new study in the Proceedings of the National Academy of Science (PNAS). Jana Vamosi, Ph.D, postdoctoral associate at the University of Calgary and Tiffany Knight, Ph.D., assistant professor of biology in Arts & Sciences at Washington University in St. Louis, and their c...

Sex: It's costly but worth it. Just ask a microbe

The next time you mutter about the high cost of relationship maintenance, take comfort in knowing that microbes share your pain. In the first study to examine the cost of sexuality in microbes, Jianping Xu, associate professor of biology at McMaster University, found that sex exacts physical, morphological and behavioural stress on microbes. His findings are published in the recent edition of Ge...

Face perception is modulated by sexual orientation

New research indicates that an area of the brain thought to act in reward circuitry may represent a phase in visual processing during which sexual orientation modulates how we perceive individual faces. The findings are reported by Felicitas Kranz and Alumit Ishai of the University of Zurich. Of all the visual skills possessed by humans, face recognition is arguably the most developed. Pa...

Uncovering sex-change secrets of black sea bass

In a former cowshed on the edge of the University of New Hampshire campus, David Berlinsky, assistant professor of zoology, peers into a big blue plastic tub. Inside, black sea bass circle slowly in the dim light. The converted barn is now an aquaculture research facility for the College of Life Sciences and Agriculture, and home to Berlinsky's latest research. Black sea bass feature promi...

Sex chromosome genes influence aggression andmaternal behavior, say UVa researchers

It has been well documented that, across human cultures and in most mammals, males are usually more aggressive and less nurturing than females. It's simple to blame male hormones, like testosterone, for male behavior such as aggression. But maybe it's in our genes, too. Indeed such social behavior also has a genetic basis, according to new research on mice by neuroscientists at the Univers...

Teens unaware of sexually transmitted diseases until they catch one, Carnegie Mellon study finds

Most sexually active teenage girls know relatively little about sexually transmitted diseases (STDs) until it is too late, according to a paper by Carnegie Mellon University researchers that will be published in the January edition of the Journal of Adolescent Health. "For the most part kids learn about sexually transmitted diseases when they are getting diagnosed with them," said Julie Do...

First 'encyclopedia' of nuclear receptors reveals organisms' focus on sex, food

In creating the first "encyclopedia" of an entire superfamily of nuclear receptors ?proteins that turn genes on and off throughout the body ?UT Southwestern Medical Center researchers found that certain receptors form networks and interact to regulate disease states and physiology in two main areas, reproduction and nutrient metabolism. Receptor networks also have key roles in metabolism's...

Genetic tug of war determines sexual differentiation

Whether or not a fertilized mammalian egg ultimately develops into a male or female is determined by the winner of a tug of war between two different genes encoding signaling proteins and the divergent pathways they control, according to a new study led by Duke University Medical Center cell biologists. In their experiments in mice, the researchers found that two specific genes, Wnt4 and F...

Female birds boost up their eggs when hearing sexy song

In a new study published in the latest issue of Ethology researchers show that female songbirds can alter the size of eggs and possibly the sex of their chicks according to how they perceive their mate's quality. The researchers played back attractive ("sexy") songs and less attractive control songs of male canaries to female domesticated canaries. When the females started egg-laying they...

Study challenges myth that sex late in pregnancy hastens birth

A new study debunks the widely held belief that engaging in sexual intercourse during the final weeks of pregnancy can hasten labor and delivery. In fact, just the opposite was true in 93 women studied at Ohio State University Medical Center. Women who were sexually active in the final three weeks of their pregnancies carried their babies an average of 39.9 weeks, compared to average deliv...

Embryonic selection of sex avoids conceiving blind children

The Assisted Reproduction Unit at the Quirón Hospital in Donostia-San Sebastián has managed, for the first time in the Basque Country, to successfully carry out an embryonic sex selection in a woman who is a carrier of the disease Retinosis Pigmentaria, linked with the X chromosome ?in order to avoid giving birth to a male child. Retinosis Pigmentaria is a hereditary illness of the eyes of...

Sex and the heart: It's not what you think

A surprising new study finds that women in their 60s have as many risk factors for heart disease as men, and by their 70s have more, according to research led by demographers at the University of Southern California. The findings, published in the current issue of the Journal of Women's Health, reflect a change from previous decades when older men were at greater risk for heart disease. In...

New clues to how sex evolves

Sex is a boon to evolution; it allows genetic material from parents to recombine, giving rise to a unique new genome. But how did sex itself evolve" Researchers at the Department of Energy's Lawrence Berkeley National Laboratory and the University of California at Berkeley have found clues to one part of this complex question in ongoing studies of the nematode Caenorhabditis elegans. Abby...

With fruit fly sex, researchers find mind-body connection

Male fruit flies are smaller and darker than female flies. The hair-like bristles on their forelegs are shorter, thicker. Their sexual equipment, of course, is different, too. "Doublesex" is the gene largely responsible for these body differences. Doublesex, new research shows, is responsible for behavior differences as well. The finding, made by Brown University biologists, debunks the...

Syphilis rate on rise in US gay, bisexual men

Armed with more than a decade’s worth of statistics, researchers are sounding a new alarm about growing rates of syphilis among gay and bisexual men. The overall number of syphilis cases in the United States fell from 50,578 in 1990 to just 7,177 in 2003 perhaps because of a nationwide prevention campaign aimed at heterosexuals. Nevertheless, gay men have seen their rates rise significantl...

New measure of sexual arousal found for both men and women

According to a new study published in the latest issue of The Journal of Sexual Medicine and conducted in the Department of Psychology of McGill University, thermography shows great promise as a diagnostic method of measuring sexual arousal. It is less intrusive than currently utilized methods, and is the only available test that requires no physical contact with participants. Thermography is cur...

1/3 of sexually active older adults with HIV/AIDs has unprotected sex

One out of three sexually active older adults infected with HIV has unprotected sex, according to a study by Ohio University researchers. A survey of 260 HIV-positive older adults found that of those having sex, most were male, took Viagra and were in a relationship. AIDs cases among the over-50 crowd reached 90,000 in 2003. According to the Centers for Disease Control and Prevention, they...

Mitochondrial genes move to the nucleus -- but it's not for the sex

Why mitochondrial genes ditch their cushy haploid environs to take up residence in a large and chaotic nucleus has long stumped evolutionary biologists, but Indiana University Bloomington scientists report in this week's Science that they've uncovered an important clue in flowering plants. "Plants that reproduce clonally or are capable of self-pollinating have transferred more genes from...

Bird sex is something else

We’ve all heard about the birds and the bees. But apparently when it comes to birds, they have an unusual take on his and hers ?and the difference is genetic. Species with differentiated sex chromosomes (X and Y in humans, for example) get around the fact that males and females get different-sized portions of sex chromosome genes with a balancing act geneticists call dosage compensation. But res...

No sex for 40 million years? No problem

A group of organisms that has never had sex in over 40 million years of existence has nevertheless managed to evolve into distinct species, says new research published today. The study challenges the assumption that sex is necessary for organisms to diversify and provides scientists with new insight into why species evolve in the first place. The research, published in PLoS Biology, focus...