New research shows serotonin levels in influence gay and straight behavior—at least in mice.
By denise ngo — Written on Mar 28, 2011
The "nature makes us gay" vs. "nurture makes us gay" debate is ongoing. This time, it's score one for nature.
Findings published in Nature showed that tweaking serotonin levels in mice produced heterosexual or homosexual behavior, depending on the levels. Although the neurotransmitter serotonin, also known as the "happiness hormone," primarily regulates mood, appetite and sleep, it also influences sexual behaviors like erection, ejaculation and orgasm. For humans, altered levels of serotonin can mean a diminished sex drive, which commonly occurs after taking anti-depressants that increase serotonin. Are You In Love? A Brain Scan Can Tell
For mice, the lack or presence of the chemical may control sexual orientation. Scientists in China found that 50 percent of mice bred without serotonin lose their preference for females. When introduced to both male and female mice, half of the serotonin-deficient mice mounted other male mice while delivering mating calls, which are typically reserved for females. Likewise, 60 percent of the altered males showed no preference for the smell of females' genitals and bedding and were drawn to male odors instead. All of the males with normal levels of serotonin chose females, and the altered ones could be "restored" to heterosexuality with an injection of serotonin.
Although this study may open avenues to more research on the role of neurotransmitters in sexual preference, scientists warn against drawing conclusions about human sexuality from this study. Not only are the findings still in preliminary stages, but mice and humans possess completely different sexual triggers. Mice are are driven by odor; we're driven by biceps, sweet nothings and other slightly more complicated urges. The Male And Female Brain On Sex
It's not a total breakthrough in the nature versus nurture debate, but for the time being, you can tentatively consider these findings as one point for the biological component of sexual preference.
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