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By Root 262 0

used male flies with a form of yet another gene called genderblind. Males with a mutation of that gene, like the fruitless mutants, will court other males as well as females. This is simple observation—what is exciting is that the scientists went on to pin down why. The genderblind gene controls the transport of glutamate out of glial cells, which are nervous system cells that do not conduct electrical signals themselves but communicate with and support other cells. Glutamate in turn can control the synapses, those junctions between other nerve cells, and synapse strength is important in determining many aspects of behavior. By altering synapse strength either genetically or chemically, independent of the mutation, the researchers could alter, sometimes within minutes, whether the flies would court males as well as females, or only females. Then they could be switched back again. The altered males interpreted the pheromones of other flies differently than their wild counterparts because they had too many glutamate receptors at the junctions between the nerve cells. What would ordinarily be a male smell that induced other males to keep away was perceived by the mutants as stimulating.

What exactly was going on? Recall that even wild-type male Drosophila will court other males, particularly when they have recently become sexually mature. The courted males reject them, and they learn to stop trying, generally within about half an hour of getting nowhere. But the genderblind flies just don't take no for an answer, which suggested to Featherstone that what was really happening was at least partly a failure to learn from experience. Current research in his lab is focusing on how glutamate is involved in this learning process. Ironically, then, the search to find genes and chemicals associated with courtship and mating led to the discovery that learning, that most plastic of behaviors, is at the heart of the matter. Nothing could be farther from demonstrating that a gene or genes causes homosexuality.

Regardless, the media fell on Featherstone's discovery like gay-gene-seeking jackals. Perhaps because of the rapidity of the switch, commentators seemed to think that the work indicated it was possible, even likely, that scientists could develop a pill that would alter human sexual orientation, and hence be used to "cure" homosexuality, or that said drug could be used recreationally, so that one could be gay under some circumstances and straight under others. When I wrote a brief op-ed piece about Featherstone's work for the Los Angeles Times, in which I noted that the really interesting part of the research, the role of glutamate, had gotten ignored in all the brouhaha, I got emails accusing me of promoting genocide of homosexuals. Another article's title demanded, "If There Was a Gay-Straight Switch, Would You Switch?" Never mind that not a single answer to the question appeared in the article itself. Even some of Featherstone's colleagues questioned his use of the word homosexual in his paper on the work, calling it "tabloid language."

Aside from the fact that anyone who thinks that "homosexual" is tabloid language hasn't been spending nearly enough time at the grocery store checkout, much of this reaction was seriously off base. Featherstone points out that his work looked at courtship behavior that was indeed directed at members of the same sex, hence homosexual. But many people use the word to talk about sexual orientation, or the preference for one kind of partner over another. As he says, "Our data as well as recent data from mice suggest that mate choice is not some sort of 'compass arrow' that can only point at one target.... Let me make an analogy: mate choice is a lot like food choice. The fact that I like corn dogs doesn't keep me from liking pizza. They are separate sets of sensory stimuli, to which I can respond independently.... 'Homosexual' and 'heterosexual' are simply descriptive terms that define particular types of mate choice, same as 'corn dog' and 'pizza' define particular types of food."

This still doesn't