Barash not so enlightening on the paradox of human homosexuality
Posted 02 Jan 2013 / 1The Chronicle of Higher Education “The Evolutionary Mystery of Homosexuality”
It is interesting that Barash focuses so heavily in this article on traditional population genetic explanations for the “paradox” of homosexuality, especially when it is becoming so clear that single-gene approaches to human evolution make very little sense.
Barash also makes a really weak argument for the “biological” basis of homosexuality. I am surprised to see him making an implicit “nature versus nurture” argument by suggesting that homosexuality cannot be “learned”. What about an interaction between environment and genes? Is being gay really that hard-wired? If so, why is it not more clearly predictable using population genetic explanations? The lack of evo-devo nuance here is frustrating.
Barash’s “reasonable summary” that there is genetic control of homosexuality seems premature to me, especially given recent evidence for an epigenetic basis of homosexuality.
I do find the idea that cross-cultural rates of homosexuality are comparable to be compelling, and although Barash’s list of explanations is incomplete it is useful.
A Minor Post, Articles, Evolution, Gene by Environment Interactions, Genetics, Group Selection, Kin Selection, Natural Selection, Population Genetics, Reproductive Fitness, Sex and Reproduction
There is actually no evidence of an epigenetic basis of homosexuality; it is only a mathematical model at this point. I personally think that homosexuality in sheep and humans has the same basis: selection against bisexuality. Both male sheep (for sure) and male humans (probably) were polygynous and bisexual; the shift toward heterosexuality and social monogamy may explain exclusive homosexuality as a biproduct.