October 25, 2007 -- Sexual Orientation Controlled in the Brains of Worms

Attraction is mystery we might not want to solve. You know, it’s sexier when science can’t explain it, and besides, we got to keep those freelance poets in business.
 
But science never lets anything alone, so research published this week in Current Biology reveals that our sexual orientation might, in fact, depend on the wiring of our brain at puberty. At least in nematode worms.
 
Originally, scientists thought that special smell neurons in male worms controlled their sexual preference. But experiments show that core neurons, which are common to both males and females, are really what makes the critical difference in same-sex attraction.
 
Scientists activated a gene called fem-3 in female brains during puberty – and while this did not change their body or genitalia, it did alter their sexual preference. The females liked other females.
 
So it appears orientation is not due to the sex hormones but more the wiring of the brain.
 
But, of course this is worms, and humans are a tad more complex…I mean our social behavior has some influence, and really, a knowing look across a crowded room is much more subtle than bumping into something that smells good in the dirt.