May 10, 2005 | Sex & Society

Gay brains smell different

Gay men's brains respond differently from those of straight men when they smell a chemical derived from the testosterone hormone, according to a Swedish study published today.  When exposed to a testosterone derivative produced in men's sweat the  parts of the brain linked to sexual activity were activated in straight women and in gay men - but not in straight men - the researchers found.

The researchers say the study is further evidence that sexual orientation is biologically determined. It is also evidence of human  "pheromones," chemicals present in sweat that act like hormones on the recipient's brain. The fragrance industry would just love to isolate human pheromones for use in their products.

There are a number of criticisms of the study:

• the size of the sample is very small (36 participants)
•  people may be conditioned to react to what they smell - if you smell man-sweat every time you have sex, then the scent may be associated with sexual activity. Chicken or egg?
• demonstrating a biological cause to homesexuality may lead to its re-medicalization; if there's a cause, then perhaps there is a cure.

So there is a scientific explanation for why you sprout a woody when you sneak a sniff of some hots guy's sweaty jockstrap. 
[The New York Times]