I do not think that the mere persistence of a trait argues for its adaptiveness. After all, the only question is whether it is able to propagate itself. It may produce unwanted effects, and yet still permit reproductive transmission, all the more if it is recessive, and therefore does not necessarily affect carriers.
Second, a trait that may be beneficial if confined to a small proportion of the population may very well be harmful if it exceeds certain limits. Therefore, arguments about the beneficial nature of homosexuality must always rest on the assumption that it is the exception, not the rule.
Third, although there is some evidence of a genetic predisposition to being gay, the famous twin study (which was itself attacked for poor methodology) could at best assert a 50% correlation. Thus, although there may be an adaptive explanation for the traits leading to the predisposition, that does not mean that there is an adaptive explanation for homosexuality per se.
Fourth, so far, there is the merest gossamer of speculation about the adaptiveness of homosexuality. The fact that homosexuals may exhibit desirable characteristics in a cultural context does not speak to the evolutionary question, because it cannot be shown how much has to do with genes, how much with psychological pressures operating on the homosexual sensibility. |
