22

Nov

2010

Human homosexuality: How unique are we really?

Written by: Aldo Poiani

 

Homosexuality is at the centre of some major debates in society right now. Not that this is something really new, homosexuals have been regarded as a “thorn in the flank” of Western culture since at least the 19th century. What is new now is that most people have access to more and better information and, potentially, should be better equipped to counter-argue superficial opinions based on traditional prejudices and beliefs. Various arguments have been put forward to regard homosexuality as contrary to human nature, with some of those arguments being wrapped up in some kind of biological skin. The first argument goes more or less like this: we are still here because there has been a long chain of past sexual encounters between women and men, had those sexual encounters been just between women and just between men we wouldn’t be here (the “biological extinction” argument). Ergo, heterosexuality is intrinsically necessary for the maintenance of the species. This argument is obviously quite compelling and no serious biologist would possibly deny that reproduction is central to the maintenance of any species. The problem is that to reproduce there is no need to have a heterosexual orientation, you only need to be biologically able to conceive, and to actually engage in sexual intercourse with somebody of the other sex: a willing partner in reproduction. Both bisexuals and exclusive homosexuals can do that, they are perfectly capable reproductive individuals who can engage in sexual intercourse with a member of the other sex for the purpose of reproduction if they choose to, and some do. Whatever impediment there is in this regard is not biological, it is legal or cultural affecting paternity and maternity of homosexuals.

The second argument runs more or less like this: There is no other species known that includes exclusive homosexual individuals, so obviously this human exception is an aberration (the “biological weirdness” argument). Apart from the fact that evolution thrives in producing “exceptions to the rule”, the claim as such is false, exclusive homosexual males have been thoroughly described and investigated in sheep (Ovis aries), those rams are truly exclusive homosexuals. But then the immediate counter-argument goes: “Oh yes, those rams, of course. But, you see, those are domestic animals, they are not the product of a natural process.” Unfortunately for some of those apologists, those domestic rams were not artificially selected to mate with other rams, they just popped up unexpected during a process of domestication that selected for increased reproductive output of ewes. So, as breeders were selecting for females that reproduced more, surprise surprise they got some males that did not reproduce. Believe it or not, we evolutionary biologists have got a name for that: it’s called sexually antagonistic selection. And lo and behold, the same pattern has been observed among human male exclusive homosexuals: they tend to be born in large families and tend to be among the youngest in their brothership. The third argument is often used when everything else fails: okay, animals do it too, so what, all species are unique and in our uniqueness homosexuality is a pathological aberration (the “biological pathology” argument). Not that easy, in evolutionary terms to prove that homosexuality is a pathology you have to prove that it is maladaptive. Judging from the treatment of homosexuals in most Western societies, who would be surprised if some homosexuals do develop mental problems, thus feeding the “pathological” arguments of homophobes? Have you ever lived in a social environment where you are persistently and consistently ostracised and discriminated against? No? Lucky you! Just try once, just for the sake of experiment, I guarantee you, it’s not fun! When exclusive homosexuals are fully accepted in their social milieu, they are not only perfectly healthy mentally, but they are a pretty happy and fulfilled bunch, displaying a tendency to cooperate with their immediate family (evolutionary biologists call this “kin selection”) and society at large (this is called “mutualism” and “reciprocal altruism”). Finally, detractors of the evolutionary basis of homosexuality often forget that, apart from exclusive homosexuals, homosexual behaviour is also expressed by bisexuals, and bisexuality is a pervasive sexual orientation among primates and many other social mammals.

Does all this puzzle you, amaze you, or even irritate you? Do not believe it? Just read my book and then let me know what you think.

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About the Author: Aldo Poiani

Aldo Poiani is an evolutionary ecologist at Monash University, Australia and the author of Animal Homosexuality: A Biosocial Perspective (2010). He has studied social behaviour, sexual behaviour and parasitism in birds, having published widely in the fields of avian cooperative breeding and host–parasite interactions, incl...

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