Lesbilicious - the web’s tastiest lesbian magazine

New brain-scan research published this week indicates that being gay or straight is a biologically fixed trait.

A team of Swedish scientists from the Karolinska Institute in Stockholm compared the brain shapes and sizes of 90 people. They found that gay women and straight men tend to have a slightly larger right hemisphere, while gay men and straight women tend to have symmetrical brain hemispheres.

The scientists also measured blood flow to the amygdala and looked at how this area connected to other parts of the brain. The amygdale is the part of the brain that directs our attention to biologically important stimuli in our environment, such as attractive partners, food, or threatening faces, and it also controls fear and aggression.

Studying the amygdale showed that once again, gay men’s brains have similar patterns to straight women, and gay women to straight men.

In gay men and straight women, the connections from the amygdale were made mainly into regions of the brain that manifest fear as intense anxiety.

Ivanka Savic, the scientist leading study, says that this data corresponds with previous research which found that women are three times more likely to suffer from depression than men. Gay men also have higher rates of depression than straight men, but it is not known whether this is due to biological or social factors.

In gay women and straight men, however, the amygdale connects mainly with the regions of the brain which trigger the ‘fight or flight’ response. “It’s a more action-related response than in [straight] women,” Savic told New Scientist magazine.

Previous studies have also shown differences in brain structure and activity between gay and straight people, but most of the studies measured responses which could have been learned, such as rating the attractiveness of male or female faces.

To avoid this problem, Savic’s team chose to look only at brain features which are fixed at birth and are not altered by learning or cognitive processes.

“This is the most robust measure so far of cerebral differences between homosexual and heterosexual subjects,” says Savic.

Are gay people really born and not made? Is this the end of the nature vs nurture debate? Lesbilicious spoke to some experts to find out more…

Posted in: Campaigns & Politics, Community, Health |