I think the answer lies quite ahead in how "natural" it is. I am looking at an overpopulation problem, I am looking at chemicals only, I am thinking Darwinian adaptation, and reproduction. The condition is natural.....no doubt, it boils down to feelings, not simple sex. The idea that population is an issue and that homosexuals will prevent adequate procreation is popular. I remember the Gaia hypothesis that was an idea that there is a pervasive consciousness that infuses all earthbound life....even the earth itself. This is not a god-concept, more or less a validation of the miraculous causes and effects that we endure as Earthlings in relationship to the sun. I like the idea that the Earth is getting full and biology and culture are shifting toward a solution, in part. Procreation is a major problem!!! I am on a limb here, please forgive but as evolution comes into play what advantages do straight vs homo people have right now? Given that, the choice for a "family" exists for anybody and gays can reproduce through multiple ways. Perhaps, the absence of the traditional family, better health, and disposable income may become survival mechanisms. Too many of us will destroy us all. Science makes traditional procreation a non-issue, regardless of sexuality, you may become a mother or father. The Idea that this is un-natural is where I begin to understand however, I feel somehow it is advantageous.