As Wainberg says, the assumption that there’s a clear line between heterosexual and homosexual behaviour “is out of step with the field of sexuality research. It is not evidence of nature at work; rather, it is evidence of the historical forces that continue to shape our concept of relationships.”
Here's the story so far. A team of researchers, based in China and St. Louis, published a study in the journal Nature yesterday, where they announced a surprising finding: Male mice that lack the neurotransmitter serotonin don't seem especially picky about whether they have sex with males or females.
Ordinary male mice, with ordinary levels of serotonin, tend to exhibit a clear preference for female mice: they're more interested in females' scents, they try to mount females when they're around, and they serenade them with high-pitched mating calls.
Male mice with low serotonin levels, though, will spit squeaky mouse game to pretty much any mouse. They'd exhibit typical mating behaviors whether confronted with male mice, female mice, or a mixed group. It seemed like the low-serotonin males simply didn't care with whom they mated.
So how did this story get reported? "Scientists 'Turned Mice Gay' Using Hormones," declared Business Insider. "Scientists Turn Mice Gay by Depriving Them of Serotonin," said Gawker. "Blocking Serotonin Makes Mice Sorta Gay," said New York.
Well, no. "Gay" seems like the wrong word here. It would be just as accurate--or possibly more accurate--to say, as Ed Yong does at Discover, that "a lack of serotonin could have just made for hornier mice that were happy to indiscriminately mount anything within range." If the mice were gay, they wouldn't have continued to try to have sex with females, right?
It's also probably a mistake to speculate that there's a link in humans between serotonin levels and homosexuality, as Gawker's Seth Abramovitch does. "Feeling blue? Listless? Down in the dumps?" Abramovitch asks, alluding to the link between depression and low serotonin levels, which often go hand in hand. "Then you might be gay!" Again, no. BBC News quotes a neuroscientist at the Babraham Institite who says that "any potential links between serotonin and human sexual preferences must be considered somewhat tenuous."
Really, it's a bad idea to use terms like "gay" and "straight" when talking about mice at all. "When mice with normal levels of serotonin are given a choice between males and females, they will mount the male at least 20% of the time," points out Ed Yong. "This, and the widespread nature of homosexual behaviour in animals, supports the idea that sexual preference is more of a continuum." (Wire note: we're not scientists, but it's also possible that they're mice, and don't think in terms of preference, and that it would be unwise to categorize their behavior anthropomorphically.)
Yong goes on to quote the Columbia professor Milton Wainberg: