In fruit flies, homosexuality is biological but not hard-wired
The gene is called "genderblind", and "it has the unusual ability to transport the neurotransmitter glutamate out of glial cells -- cells that support and nourish nerve cells but do not fire like neurons do. Previous work from his laboratory showed that changing the amount of glutamate outside cells can change the strength of nerve cell junctions, or synapses, which play a key role in human and animal behavior."
"Based on our previous work, we reasoned that GB mutants might show homosexual behavior because their glutamatergic synapses were altered in some way," said Featherstone. Specifically, the GB mutant synapses might be stronger.
"Homosexual courtship might be sort of an 'overreaction' to sexual stimuli," he explained.
To test this, he and his colleagues genetically altered synapse strength independent of GB, and also fed the flies drugs that can alter synapse strength. As predicted, they were able to turn fly homosexuality on and off -- and within hours.
"It was amazing. I never thought we'd be able to do that sort of thing, because sexual orientation is supposed to be hard-wired," he said. "This fundamentally changes how we think about this behavior."
Now, of course this isn't going to be an exact model for human sexuality, we're much more complicated psychologically than fruit flies, but it is quite interesting. And even if it does have some kind of analog in human sexuality, I very much doubt we'll some day be able to turn homosexuality on and off, as I said we're just too complicated. Although that raises some interesting questions about whether or not we would even want to, it seems to me like we wouldn't, but I suppose that would be an intensely personal decision. At the very least this is yet more evidence that homosexuality is biological, and not just "a choice" that can be made on a whim. Unfortunately the people who believe homosexuality is a choice will never be persuaded by evidence.
Another interesting aspect of this research is that fruit flies can show homosexual behavior. I didn't even realize that animals as simple as insects could show it at all, I guess homosexuality even more ingrained into nature than I thought. All the more reason to laugh at the bigots who call it unnatural and a sin. Idiots.