Brain Cluster Linked To Orientation

A small part of the brain that controls sexual behavior, the sexually dimorphic nucleus in the hypothalamus, is about twice as large in men as in women, except for many gay men. In 1991, neuroscientist Simon LeVay examined this region in human autopsy brains and found that in most gay men it was significantly smaller than in straight men, closer to the size seen in women. Researchers then looked at a comparable nucleus in domestic rams and saw the same pattern, with homosexual rams showing a smaller male-typical cluster than heterosexual rams.

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