Homosexuality and Evolution
The Economist has a summary of interesting new research on the evolutionary aspects of homosexuality. The question has been why has homosexuality persisted in the population despite the pressures of natural selection; the assumption being that homosexuals, not having any children, do not pass on the homosexuality genes to the next generation.The conventional idea has been that "the relatives of those who are gay gain some advantage that allows genes predisposing people to homosexual behaviour to be passed on collaterally", and in particular that "there is evidence that male homosexuals, at least, are more likely than average to come from large families, is that the genes for gayness bring reproductive advantage to those who have them but are not actually gay themselves. Originally, the thought was that whichever genes make men gay might make women more fecund, and possibly vice versa."
But new works hows that the fecundity advantage actually accrues to relatives of the same sex as the homosexual relative.
http://www.economist.com/science/displaystory.cfm?story_id=12465295
