by Monika Rice

 Men and women think differently. We know that from experience and most recently from various kinds of brain scans. But what about the brains of gays and lesbians?
A recent study published by scientists at the Karolinska Institute, Sweden, showed that brain activity in homosexuals was similar to that of heterosexuals of the opposite sex. Using MRI and PET scans, the researchers studied the brains of 90 heterosexual and homosexual subjects and found that although the right hemisphere was slightly larger than the left in heterosexual males and lesbians, the same two hemispheres in the brain of gay men and straight women were symmetrical.

In terms of connectivity, or blood flow to the amygdala — the part of the brain responsible for emotional learning and processing — in gay men it resembled straight women’s, and in lesbians it resembled straight men’s. In other words, gay men and straight women, and lesbians and straight men share the same characteristics in the brain that govern emotions, mood, and anxiety.

Although researchers could not say with certainty whether the brain shapes of gays and lesbians is inherited or due to hormonal exposure in the womb, such as testosterone, these observations motivate further investigations in terms of the neurobiology of sexual orientation.