Gay Men Respond Differently to Pheromones than Straight Men

The sexual area of a gay man's brain works a lot like that of a woman when exposed to a particular stimulus, researchers say.
In an experiment, men and heterosexual women sniffed a chemical from the male hormone testosterone. The homosexual men's brains responded differently from those of heterosexual males, and in a similar way to the women's brains.
"It is one more piece of evidence ... that is showing that sexual orientation is not all learned," said Sandra Witelson, an expert on brain anatomy and sexual orientation at the Michael G. DeGroote School of Medicine at McMaster University in Ontario, Canada.
Witelson, who was not part of the research team, said the findings clearly show a biological involvement in sexual orientation.
The study, published in Tuesday's issue of Proceedings of the National Academy of Sciences, was done by researchers at the Karolinska Institute in Stockholm, Sweden.