Feeling blue? Listless? Down in the dumps? Incapable of experiencing pleasure in any way, shape, or form? Then you might be gay!
That's the conclusion that was sort-of arrived at by scientists in China, who have been studying the effect of serotonin on the sexual preferences of male mice. Their study, published in the current Nature, found that mice bred to have brains unreceptive to that mood-regulating neurotransmitter lost their previous impulse to mate with females. Remove the females from the equation entirely, and you got something resembling an all-rodent, dioramic representation of Fire Island Pines:
When just a male was introduced into the cage, the modified males were far more likely to mount the male and emit a "mating call" normally given off when encountering females than unmodified males were. [...]
However, a preference for females could be "restored" by injecting serotonin into the brain.
The implications of all this on the gay movement are touchy to say the least, and potentially even devastating. For starters, just try dancing to the lyric, "I'm on the right track baby / I was serotonin-regulated this way." It can't be done. [BBC]