Homosexuality and Natural Selection.

CDarwin wrote:

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But like the religious people I talk to the Gay community in Santa Monica seem to want to see evolution as a reason they exist.
It mat be correct that Homosexuality is genetic but yet unproven.

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OK, here is my understanding of a possible solution. I’ll write this assuming homosexuality is completely genetic, which is the worst possible scenario for our discussion, since any bit environmental only makes it easier for homosexuality to exist and to have survived natural selection. Also, it is quite clear to me that something that is selected against slowly dies out. Therefore, since homosexuality exists today, there must be some explanation that makes it selected for.First, most traits are polygenic - that is many genes contribute to them. This is unlike eyecolor, or sex determination, which are monogenic. For example, skin color is controlled by more than one gene - hence the fact that there are intermediate skin colors, not just “all black” or “all white”. So it is reasonable to guess that sexual orientation is polygenic. This fits the data too. Kinsey and other studies have shown that people fall on a range from pure homosexual, through bisexual, to pure heterosexual, with plenty of points in between. Thus, if some point in the middle is selected for, then the genes for both will be selected for. Pure homosexuality can therefore be selected against. For instance, say the alleles show incomplete dominance, like skin color, and the alleles are S for straight and s for gay, and futher say it is on 4 loci (complete guess, more or less still works). So a completely straight person is SS SS SS SS, completely gay is ss ss ss ss, and most people are, say, pretty much straight (SS SS Ss Ss), but some are bisexual (Ss SS ss ss) or some such.Now - if all that is reasonable, then why would some point in the middle be selected for instead of (SS SS SS SS)? Remember that the optimum place can be anywhere, as long as it isn’t either extreme. In other words, if SS Ss Ss SS is the optimum, then the s allele still survives, and some people will end up, by mendelian chance, with something like ss ss Ss ss, and be gay.The ability and desire to sometimes have homosexual sex seems easy to be advantageous. One way is to look at the Bonobo chimp (our closest relative after the regular chimp). They use sex like we use a handshake, and just about as often and as indiscriminately. They have sex with whoever is needed to solve social problems. Our chimp ancestors could have been like that, or even a little like that, and hence we have the s allele.Similarly, in the rough Pleistocene, sex may have been rare to get. You have to have not only the right kind of person (not a sibling, too old or too young), but you also have to get the right sex. Would a person with some bisexual nature have been able to have sex a little more often, thus keeping from getting rusty or to enhance social standing? Seems feasible. Yes, in really hard times that could waste protein, but it’s not hard to imagine us only being turned on when we were healthy (that’s how it is today, after all).So there we go, no problem with evolution “planning for population control” or any such stuff, and still genetic, with no selection problem. What do you think?-EquinoxEdited by Equinox, : Really funny typo - typed "Bono" instead of "Bonobo".