On 2015 Oct 16, David Keller commented:

How did same-sex preference genes persist despite their effects on reproduction?

Evidence suggests the existence of genes which promote homosexual preference. A gene which tends to decrease its own reproduction in this way must have some countervailing effect in order to persist in the gene pool.

If the same mutation which promotes homosexuality in men also increases fecundity in women, it could persist in equilibrium with wild-type alleles. The reduced number of offspring of male carriers would have to be offset by an increased number of offspring in female carriers large enough to avoid the disappearance of the gene which would otherwise occur over time.

Another possibility is that social repression of homosexuality had the paradoxical effect of promoting the survival of same-sex preference genes. Modern society's tolerance, by reducing the social pressure to reproduce, could ironically lead to the gradual disappearance of genes which promote homosexual preference.

On 2015 Oct 16, David Keller commented:

How did same-sex preference genes persist despite their effects on reproduction?

Evidence suggests the existence of genes which promote homosexual preference. A gene which tends to decrease its own reproduction in this way must have some countervailing effect in order to persist in the gene pool.

If the same mutation which promotes homosexuality in men also increases fecundity in women, it could persist in equilibrium with wild-type alleles. The reduced number of offspring of male carriers would have to be offset by an increased number of offspring in female carriers large enough to avoid the disappearance of the gene which would otherwise occur over time.

Another possibility is that social repression of homosexuality had the paradoxical effect of promoting the survival of same-sex preference genes. Modern society's tolerance, by reducing the social pressure to reproduce, could ironically lead to the gradual disappearance of genes which promote homosexual preference.