I hadn't expected this topic to draw as much response as it has, but we here at SDP and at Keloland are all about serving our public so I feel some obligation to respond to the items in my mail.
Intrepid reader William A. Williams alerts me to an article in the New York Magazine by David France, "The Science of Gaydar," that neatly summarizes some of the research on homosexuality. I knew that homosexual men were more likely than heterosexual men to have a ring finger that is longer than their index fingers. I did not know that homosexual men are more likely to have a counterclockwise "whorl" in their hair pattern. The Irish have a phrase: "Protestant hair." I forget what that means. Apparently there is also gay hair.
I would note that a lot of this research is very tenuous, and suggests differences that are marginal at best. The finger thing is present in 8% of the general population, and 23% of homosexuals. That may indicate a genetic factor, but it cannot be a gene generally responsible for homosexuality. I do not share Mr. France's preference for the term "third-sexer." Sex is clearly the wrong word, as it implies a connection to the biological process of reproduction. If homosexuals could breed with either males or females, as in some science fiction, that would be a third sex. Homosexuality is about gender and behavior.
Intrepid reader and friend of SDP, Gene Kocmich shares this amusing story about a sexually disinterested boar.
Many years ago on the farm in SD my Dad bought a boar hog that had the physical traits he though would improve the quality of offspring we bred for market. He paid $350 in 1959 for this young boar and expected great things. Well the boar would have nothing to do with the guilts and sows when they were in heat. He just wasn’t interested. My Dad returned the “queer boar” and got another from the breeder. I don’t believe pigs are affected by their environment so it was probably biological. Did this boar take a liking to other boar pigs? We never tested that outcome.
I don't suppose Gene's dad examined the direction in which the hog's tail whorled?
IR Victor Ulmer advances the conversation.
In your response, you said, in part:
I know of at least two explanations for the genetic persistence of
genetic homosexuality. One is that homosexual males made very good warriors:
pairs of lovers sacrificed their own reproductive opportunities, but promoted
the reproductive success of their heterosexual brothers and sisters. Those
siblings carried the same genes that, in the proper mixture, would produce
more homosexual warriors. That is a niche theory. Another explanation
is that some of the genes that code for adaptive traits such as sexual
attraction to the opposite sex and desire for friendship with the same sex
will inevitably, on occasion, combine in such a way as to produce
homosexuality. That seems more plausible, but we can hardly know
yet.
But do homosexual males make better warriors,
than do heterosexual males? If they do, that explanation seems to be
plausible, but whether they do, to me, seems to be totally
speculative.
It is speculative either way, but the question is not whether they are better warriors, but whether they might have filled a niche that contributed to the genes that produced their dispositions. Perhaps a pair of homosexual soldiers were more likely to sacrifice themselves together, and thus made good last ditch guards of narrow passes and bridges and such. I am speculating freely here, but this much I know: even very small fitness advantages can result in a big genetic payoff over time. In a lot of species, individuals sacrifice their own reproduction for their near kin. Maybe, in the environment of evolutionary adaptation, homosexuality had such a marginal payoff. In that case, the selection pressure for it would have outweighed the obvious pressure against it.
Secondly, Vic wonders why homosexuality should be more common than other mutations that adversely affect reproductive fitness, such as impaired male genitalia. I answer that it all depends on the balance of selection pressures. Consider the fitness not of individuals but of genes (as your reference to Dawkin's Selfish Gene indicates). If a given gene or complex array of genes adversely affects its own reproductive success by a factor of .01 (one less replication per hundred individuals), but has a secondary effect that increases its fitness by a factor of .011 (eleven successful replications per thousand individuals), the gene will be selected for. Its representation in a population will be determined by this kind of equilibrium. My guess is that any gene that is simple disadvantageous would rapidly disappear. Any that was simply advantageous would become universal. Between the two is a spectrum that accounts for the difference between 90 pound weaklings and line backers.
Lastly Vic asks:
Might not some homosexuality be related
largely to "genetic predisposition"; and might not some homosexuality be
related largely to social and cultural factors; and might not some
homosexuality be related to several or all of
those factors? Why would this issue not be similar to other
nature versus nurture controversies?
Of course. Homosexuality is probably an expression of a complex range of genes expressed in a complex range of social situations. Some persons with no biological inclination will engage in homosexual behavior for social reasons. If Caesar likes you, well, you just can't squander some opportunities. Likewise genetic dispositions may be expressed or not depending on the balance between the intrinsic strength in the individual and the social consequences. Life is more complex than checkers.
Kudos to my readers for a dialog that has kept me, at least, interested.
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