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Alex Bäcker's Wiki / The-Evolution-of-Homosexuality
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Page history last edited by Alex Backer, Ph.D. 9 years, 6 months ago

Some authors have argued that ‘‘the homosexual gene’’ has no selective advantage, but, instead, stays in the gene pool because of a high rate of mutation (Hamer and Copeland). This makes no sense whatsoever. Homosexuality occurs in 2-11% of the population (Cameron, 1993). In contrast, Down syndrome, perhaps the most common genetic abnormality in the US, occurs only in one of every 800 births. Yet if we believe the genes of homosexuals do not get passed on, then homosexuality would be as damaging a condition for genes as any genetic abnormality, and the selective pressure against it would never allow it to occur in such large numbers --whether by eliminating genes that confer proclivity to homosexuality or by selecting genes that confer protection against it. This is all the more evident when one considers that homosexuality is not uncommon in the animal kingdom, indicating it is an ancient behavior. Therefore, homosexuality must have a selective advantage for those who engage in it. What is then the selective advantage of homosexuality?


It is not engaging in sex with members of the same gender that is surprising. Sex is such a strong driver of behavior that it is not surprising to see it used to confer pleasure to, and derive pleasure from, others of the same sex, strengthening bonds and making friends and allies. What is surprising, and requires an explanation, is the preference of homosexual sex over heterosexual sex.


Homosexuality appears to manifest itself under particular environmental circumstances.  NARTH writes: Through meta analysis of the modern empirical studies, a research team concluded: "With only a few exceptions, the male homosexual declares that father has been a negative influence in his life... There is not a single even moderately well‑controlled study that we have been able to locate in which male homosexuals refer to father positively or affectionately." (Fisher, Seymour and Roger Greenberg (1996), Freud Scientifically Reappraised: Testing the Theories and Therapy. New York: John Wiley & Sons.) 


I argue that homosexuality, and in particular male homosexuality, evolved as an adaptive response to a dangerous environment in which a male grows up lacking support by his father, putting him at risk in primitive societies where competition for females could lead to genetic death, either by murder or lack of mate availability. A male with a bad relationship with his father was traditionally less likely to succeed and secure a mate. Homosexuality serves three adaptive purposes in those cases:

1. By making the homosexual male apparently no longer a threat to other males' reproductive success, a homosexual male increases his survival probability.

2. By virtue of the same, the homosexual secures access to females that would otherwise be kept off limits for him by dominant males.

3. Homosexuality can secure a homosexual the favor of friends, which can increase his status and survival probability. But again, note that #3 alone would not explain the preference of homosexual sex over heterosexual sex.


Yet all of these would be for no selective advantage if genes of homosexuals did not live on in the following generations. There are two, non-mutually exclusive ways for this to happen. One possibility is that homosexuals further their genes by helping raise their relatives' progeny.  But the benefit of this seems rather little to counteract the drastic fitness reduction of leaving no direct descendants. More likely is that homosexuals propagate their genes via a more traditional method: heterosexual sex. Through the three mechanisms described above, a homosexual increases his chances of engaging in heterosexual sex undetected. Thus, I postulate that homosexuality evolved early on in animal evolution, in species where multiple males court females (or viceversa), as a mechanism for non-dominant individuals to appear less threatening to the reproduction of other individuals of the same sex, allowing them to sneak in a round of heterosexual sex every now and then.


A prediction of this theory is that most homosexuals actually engage in heterosexual sex at some point of their lives. A second prediction is that homosexuality should be most common in situations where an individual is at risk entering the general pool of sexual competition.


P.S. I was recently provided with anecdotal evidence in support of the first prediction above, namely that at least some avowed homosexuals pursue women and display sexual arousal when interacting closely with attractive members of the opposite sex.



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