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The role of pheromones and mating is definitely cool.  I've heard in the past that we sense that someone has a foreign immune system by how much they stink.  The worse they stink, the greater the difference in immune systems, the better the mate.  Anyone know if this holds any validity?  Just curious.  I suppose this might just something derived from the idea that sweat/body odor could potentially be better for attracting a mate than perfume. 

Anyway, I came across a study that I thought was pretty cool.  The study was covered in an article titled Pheromone Attracts Straight Women and Gay Men published in NewScientist.  Ivanka Savic lead a research team in Sweden and conducted experiments on pheromones.  In one experiment, Ivank Savic et al. found that smelling a male pheromone stimulated the same regions of the brain in women and gay men!  The pheromone used was a testosterone-derived chemical, AND, found in male sweat.  In both women and gay men, this pheromone triggered activation in the anterior hypothalamus and medial preoptic area.  There was no such activation in heterosexual men, but heterosexual men did show activation in these areas in response to EST (from women).  While there are no cause-and-effect conclusions to be drawn (whether AND triggered activation in men causes homosexuality or if AND triggered activation is the result of homosexuality), this research still shows an interesting correlation between brain function and sexual behavior.  Ivank Savic et al. believe that these areas are involved with processing hormonal and sensory inputs to form outputs of sexual behavior.  As there are no cause/effect conclusions, one is left to wonder how much the brain has control over behavior and how much behavior has control over the brain.