A few months ago, I was talking with a friend about Universal Darwism and the power of genetics, and without hesitation she asked, “Well, what about homosexuality? Surely that would have been removed from the gene pool centuries ago?”. As the evolutionary pragmatist, I completely agreed with her. If being gay was indeed nature over nurture, it would have been removed from the gene pool millenia ago, but the liberal in me felt that homosexuality must be genetic (as opposed to a life choice etc.). This conflict (along with the obvious observation that homosexuality is still pervasive in society) had me utterly stumped.
Let’s tackle the problem of evolving homosexuality out of the gene pool first — why did I believe that homosexuality should have been breed out? Imagine two groups, Group A, which makes up 99.9% of the population and Group B, which makes up the remaining 0.1%. Now imagine that Group B is a mere 1% more efficient at reproducing than Group A. The chart below shows how the two populations would progress (as a percentage of the total population) if Group A had 2 children each and Group B at 2.02 (1% more).
Unbelieveably, despite only making up 0.1% of the initial population, it takes as little as 700 generations for Group B to equal Group A and under 1,400 for their positions to be reversed! Anyone with a financial/economic background will appreciate the power of compound interest here, the same phenomena is exacerbated when applied to evolution, given both the size of the populations and years over which we look at the effects.
So what does this have to do with homosexuality? Simple — homosexual partners cannot reproduce (naturally), therefore cannot pass their “gay gene” down to their children. So, as in the example above, if a 1% decrease in reproductive capability leads to practical extinction within 1,400 generations, how has homosexuality (with a 100% decrease in reproductive capability!) not been erased after 50,000 years? Continue reading “Homosexuality: Nature’s True Altruists?”