I'm unsure of the actual mechanisms involved - undoubtedly a mixture of nature and nurture. But to really understand why homosexuality persists and isn't bred out, and may in fact be an evolutionary advantage, we need to look at humans as members of a community instead of in isolation.
Why do humans live so long, in the case of women, well past reproductive age? - because a healthy tribe benefits from the wisdom and extra childcare help of grandparents.
Why do disabilities and other genetic quirks persist? - because a healthy tribe thrives on division of labour, with different personalities and abilities making a tribe adaptable to environmental pressures.
Why do humans feel a strong sense of altruism, especially towards related humans? - because the tribe's collective 'selfish' genes are not only passed on through one's own offspring, but through related offspring such as nieces/nephews.
Similarly we could look at homosexuals as being not only, not harmful enough to be bred out by natural selection, but actually as a useful trait, because the tribe might benefit from having one less adult reproducing, but one more adult who will still work hard to protect others' offspring. I've also heard of a theory that homosexuals/asexuals in prehistoric times may have been chosen as shamans/priests and not expected to reproduce but provide spiritual guidance to the tribe.
Homosexuality has caused conflict through the ages, but think of all the eras where it might have been viewed differently (ancient Greece for example, where male/male relationships were encouraged) and actually lead to less conflict. All the millenia that straight people have been having gay babies, there must have been advantages.
Perhaps something inherent and persistent in human nature and human culture, that you have a 10% chance of growing up to be gay.
Last edited by CaveWeirdo; 08-06-2012 at 05:47 AM.
Start weight: 238 lbs (March 2012)
Current weight: 205 lbs (July 2012)
Loss so far: 33 lbs!!!
WOE: Primal + IF
Movements: Hiking, sprinting.
Goal: to see my abs some time in 2013!