by exploited » Tue Oct 07, 2014 1:52 pm
As you noted, the genetic causes of homosexuality are likely numerous. I think that homosexuality is "emergent" behaviour, rather than a specific piece of coding in a particular gene. It is the result of the interaction of several mechanisms, which produces behaviour unique from any of the source material.
Humans evolved according to the evolutionarily stable strategy (ESS), so while our goal was to reproduce, it was to do so sensibly and in equilibrium. This is why we have 1:1 sex ratios, despite our long-term, best efforts to kill off women. There has to be some genetic origin for this behaviour.
It isn't that genes "know" when a girl gets killed, so they produce a pheromone, which activates a gene that diminishes male reproductive fitness. More likely, there are two or more mechanism that operate independently of another, whose interaction results in unusual but historically consistent behaviour.
So, for instance, certain men could have a gene that will result in more male offspring. This increases reproductive fitness and future reproductive potential. The flip side is that such men would almost certainly come to dominate the gene pool, which throws out ESS and results in unsustainable sex ratios. The evolutionary response for women would be the development of a mechanism that is activated by the presence of the "more males" gene, which would progressively degrade future reproductive potential by producing deviations in sexual orientation. It doesn't "code for gay," it "codes for different." Natural selection comes into this by the fact that an unequal sex ratio always results in the destruction or absorption of that population.
This would explain a number of things: the evolutionary purpose of homosexuality, why the fraternal order of sexuality exists, why it is only seen in male and not female homosexuals, and why sexuality exists on a spectrum. It is a constant evolutionary battle to maintain the sex ratio.
Last edited by
exploited on Tue Oct 07, 2014 1:56 pm, edited 1 time in total.