A couple of blows to "lifestyle choice" crap

Two fascinating neuroscience studies this week give insight into the degree to which sexual orientation is biologically mediated.

1. Last week, a study done at the Karolinska Institute in Sweden noted that men and women's brains respond differently to a suspected male pheromone, and that gay men's brains responded like those of the straight women to these signals.

   "In contrast to heterosexual men, and in congruence with heterosexual women, homosexual men displayed hypothalamic activation in response to AND [the pheromone]," Savic's team wrote.
   
   And a region of the brain called the anterior hypothalamus responded most strongly -- an area that in animals "is highly involved in sexual behavior." But other smells were processed the same in all three groups.
   
   "These findings show that our brain reacts differently to the two putative pheromones compared with common odors, and suggest a link between sexual orientation and hypothalamic neuronal processes."

   
   
2. Today, we hear that Philadelphia's own Monell Chemical Senses Center (down the block from where I work) has announced a related finding: that people's conscious responses to body odors also track with their gender and sexual orientation.

   Homosexual men and lesbian women had patterns of body odor preferences that were different from those of heterosexual men and women. In particular, gay men were strikingly different from heterosexual men and women and from lesbian women, both in terms of which body odors gay men preferred and how their own body odors were regarded by the other groups. Gay men preferred odors from gay men and heterosexual women, whereas odors from gay men were the least preferred by heterosexual men and women and by lesbian women.

   Basically, the response of others to gay male sweat was more negative than the response to that from straight men, indicating that there is tangible difference in their body chemistry.

   "Our findings support the contention that gender preference has a biological component that is reflected in both the production of different body odors and in the perception of and response to body odors," remarks Monell neuroscientist Charles Wysocki, PhD. Wysocki and Yolanda Martins, PhD co-directed the research effort.

   (Quotes taken from the Monell press release [PDF] here.)

Well, that puts things in a rather different light than people like these might think, eh?