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.
continue at The Washington Post.