Swedish researchers did MRI scans of 50 heterosexual men and women and 40 homosexual men and women and found surprising parallels. The brains of lesbians and straight men were anatomically symmetrical while the brains of gay men and straight women had a larger right brain hemisphere. Meanwhile, the amygdala of lesbians and straight men had more connections to the region that controls fight or flight reactions.
Swedish researchers have found that some physical attributes of the homosexual brain resemble those found in the opposite sex, according to an article published online June 16 in the Proceedings of the National Academy of Sciences. Other research has hinted that homosexuals may exhibit the tendencies of the opposite sex in brain behavior unrelated to sexual activity. Positron emission tomography PET scans taken by the researchers also show that in connectivity of the amygdala which is important for emotional learninglesbians resemble straight men, and gay men resemble straight women.
The study, by Professor Semir Zeki and John Romaya from the Wellcome Laboratory of Neurobiology at UCL, is a continuation of earlier work from the same lab which described brain activity in terms of romantic and maternal love. In this latest study, 24 subjects were asked to view pictures of their romantic partnersas well as pictures of friends of the same sex as their partners but to whom they were romantically indifferent, while the activity in their brains was scanned with functional magnetic resonance imaging fMRI. The subjects varied in age from 19 to 47, with their relationship lengths varying from 4 months to 23 years.
New neuroimaging research has found that gay, bisexual, and straight men have different brain responses to sexual stimuli. The fMRI study of 26 heterosexual, 28 bisexual, and 25 homosexual men found that sexual orientation was associated with distinct patterns of brain activation. In particular, the researchers uncovered that heterosexual and homosexual men showed different neural responses to erotic stimuli in the ventral striatum, an area of the brain associated with erotic desire. The erotic stimuli consisted of pictures of nude men, nude women, and lesbian or gay couples engaged in sexual contact.
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.
A scientist with a brain scanner could figure out your sexual orientation based on the symmetry of your brain, new research from the Stockholm Brain Institute hints. The findings support the notion that biological factors help determine sexual orientation and leave a specific neuroanatomical signature. Using MRI scans of gay and straight men and women, the researchers found that people who liked women — heterosexual men and homosexual women — had larger right brain hemispheres, while people who liked men — heterosexual women and homosexual men — had symmetrical brains.
British Broadcasting Corporation Home. The brains of gay men and women look like those found in heterosexual people of the opposite sex, research suggests. The Swedish study, published in the Proceedings of the National Academy of Sciences journal, compared the size of the brain's halves in 90 adults.
Researchers using brain scans have found new evidence that biology—and not environment—is at the core of sexual orientation. Scientists at the Stockholm Brain Institute in Sweden report in the Proceedings of the National Academy of Sciences USA that gay men and straight women share similar traits—most notably in the size of their brains and the activity of the amygdala—an area of the brain tied to emotion, anxiety and aggression. The same is true for heterosexual men and lesbians.
The neurobiology of sexual preference is often discussed in terms of cerebral sex dimorphism. Yet, our knowledge about possible cerebral differences between homosexual men HoMheterosexual men HeM and heterosexual women HeW are extremely limited. In the present MRI study, we addressed this issue investigating measures of cerebral anatomy and function, which were previously reported to show sex difference.
Striking similarities between the brains of gay men and straight women have been discovered by neuroscientists, offering fresh evidence that sexual orientation is hardwired into our neural circuitry. Scans reveal homosexual men and heterosexual women have symmetrical brains, with the right and left hemispheres almost exactly the same size. Conversely, lesbians and straight men have asymmetrical brains, with the right hemisphere significantly larger than the left.