What the Gay Brain Looks Like. What makes people gay? Biologists may never get a complete answer to that question, but researchers in Sweden have found one more sign that the answer lies in the structure of the brain. Scientists at the Karolinska Institute studied brain scans of 90 gay and straight men and women, and found that the size of the two symmetrical halves of the brains of gay men more closely resembled those of straight women than they did straight men. In heterosexual women, the two halves of the brain are more or less the same size. In heterosexual men, the right hemisphere is slightly larger. Scans of the brains of gay men in the study, however, showed that their hemispheres were relatively symmetrical, like those of straight women, while the brains of homosexual women were asymmetrical like those of straight men.
The number of nerves connecting the two sides of the brains of gay men were also more like the number in heterosexual women than in straight men. Gay genes? The Real Story on Gay Genes. But 21st-century Western society, and the homosexuals therein, could be something of an anomaly in human history, according to Paul Vasey, an associate professor of psychology at the University of Lethbridge in Alberta.
“Do I think the social contexts are less representative of our evolutionary past? I’d say yes,” Vasey says. “The kind of gay men and lesbian women we are familiar with in Western culture express their homosexuality as egalitarian—they’re not differentiated as far as gender.” In other times and other places, one partner typically adopts a masculine role, while the other adopts the feminine. Another problem with kinship selection studies that look only in England and, in particular, the United States, is that kinship ties for homosexuals might not be as strong as they would be elsewhere.
Vasey has therefore been studying a group of Samoans called fa’afafine, whom he describes as more of a third sex than homosexual as commonly construed. “Bullshit,” says Bocklandt. Biology and sexual orientation. The relationship between biology and sexual orientation is a subject of research. A simple and singular determinant for sexual orientation has not been conclusively demonstrated; various studies point to different, even conflicting positions, but scientists hypothesize that a combination of genetic, hormonal and social factors determine sexual orientation.[1][2] Biological theories for explaining the causes of sexual orientation are more popular,[1] and biological factors may involve a complex interplay of genetic factors and the early uterine environment.[3] These factors, which may be related to the development of a heterosexual, homosexual, bisexual or asexual orientation, include genes, prenatal hormones, and brain structure.
Empirical studies[edit] Twin studies[edit] Biometric modeling revealed that, in men, genetic effects explained .34–.39 of the variance [of sexual orientation], the shared environment .00, and the individual-specific environment .61–.66 of the variance. What causes sexual orientation? The cause(s) of sexual orientation: Nature vs. Nurture Sponsored link. This topic is continued from an earlier essay Study 16: Based on studies of identical twins who were separated at birth: There have been a number of studies of identical twins who were separated at -- or shortly after -- birth and raised apart from each other. These pairs of twins share identical DNA and yet grow up in totally different environments. Studies of such twins are the standard technique used by scientists when trying to separate the effects of nature (one's genes) from those of nurture (one's environment, culture, religion, and upbringing).
Many studies have shown that if one twin is gay, then the other twin is found to be gay slightly more than half of the time. Consider the genes for: Huntington's Disease: It has two alleles (varieties). Sometimes, as in the case of Huntington's Disease, the presence of an allele is certain to cause the disease later in life. Biologist Chandler Burr wrote: References used: Sexuality - Identity and Attraction.
Author: SuperdrewbyDate: 2001 Sexual Orientation and Gender are significantly important areas of research and understanding especially for those people who fall outside societal expectations such as Intersex's, homosexuals and bisexuals. One of the most difficult things for many people who do not identify as heterosexuals to do is understand and accept their sexuality. Psychological and cultural research has combined to create a way of understanding and analysing individual sexuality, so that we can all find our own place in society. When we are young we are taught that there are two genders (Male and Female) and one type of sexuality (heterosexuality).
Kinsey Heterosexual - Homosexual Scale The Kinsey Heterosexual-Homosexual Scale provided our first understanding of sexual orientation. The sexuality continuum is also described as a scale from black to white with varying shades of gray in between. Klein Sexuality Continuum Past: - Past refers to what or how we have acted in the past. Same-sex Attraction Is Genetically Wired In Nematode's Brain. University of Utah biologists genetically manipulated nematode worms so the animals were attracted to worms of the same sex -- part of a study that shows sexual orientation is wired in the creatures' brains.
"They look like girls, but act and think like boys," says Jamie White, a postdoctoral researcher and first author of the new study. "The [same-sex attraction] behavior is part of the nervous system. " "The conclusion is that sexual attraction is wired into brain circuits common to both sexes of worms, and is not caused solely by extra nerve cells added to the male or female brain," says laboratory leader and biology Professor Erik Jorgensen, scientific director of the Brain Institute at the University of Utah and an investigator with the Howard Hughes Medical Institute.
"The reason males and females behave differently is that the same nerve cells have been rewired to alter sexual preference," he adds. The Rules of Attraction -- for Worms Nematodes are few and far between in soil. Mom's Genetics Could Produce Gay Sons. The arrangement of a mother's genes could affect the sexual orientation of her son, according to a new study. The finding, detailed in the February issue of the journal Human Genetics, adds fuel to the decade-long debate about whether so-called "gay genes" might exist. The researchers examined a phenomenon called "X chromosome inactivation" in 97 mothers of gay sons and 103 mothers whose sons were not gay. X and Y Chromosomes are large thread-like molecules that contain an organism's genetic instructions.
Humans have 23 chromosome pairs. Even though women have two X chromosomes, only one is functional because the other is inactivated through a process called "methylation. " "It gets wrapped up in a ball and is not used with the exception of a few genes," explained study leader Sven Bocklandt of the University of California, Los Angeles. If one of the females' X chromosomes is not turned off, then there is too much genetic material, which can lead to a harmful overabundance of proteins.