Gay Men, Straight Women Have Simi...( Scans also showed similarities betwee...),Health

Scans also showed similarities between lesbians, straight men

MONDAY, June 16 (HealthDay News) - MRI and PET scan studies are showing remarkable similarities between the brains of gay men and straight women, and between those of lesbians and straight men.

For example, the brains of straight men and of gay women share certain common features: both are slightly asymmetric, with the right hemisphere larger than the left, say the Swedish researchers.

On the other hand, the brains of gay men and straight women are both symmetrical.

Similar trends emerged when scientists tracked connectivity in the amygdala, the region of the brain involved in emotional learning and in activating the fight-or-flight response. They noted strong similarities between gay men and straight women, and lesbians and straight men.

The findings are published in the current issue of the Proceedings of the National Academy of Sciences.

"This is a very interesting study demonstrating a possible neurobiological relationship in brain size between gay men and straight women," said Paul Sanberg, distinguished professor of neurosurgery and director of the University of South Florida Center for Aging and Brain Repair in Tampa.

The neurobiology of sexual orientation is a controversial topic. Some research suggests that the brain activity of homosexual individuals in areas unrelated to sex mirror brain activity in straight individuals of the opposite sex. And certain psychological studies have revealed differences in how men and women use the brain's different hemispheres for verbal tasks, for example.

For this study, researchers from the Karolinska Institute in Stockholm first performed magnetic resonance imaging (MRI) on 90 participants -- 25 heterosexual men and an equal number of heterosexual women, plus 20 homosexual men and 20 homosexual women.

The right hemispheres of straight men and gay wo
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