He's not saying that they shouldn't exist today, just that their genes will never make it back into the collective gene pool, stopping their traits and characteristics from ever propagating forward.
But that's not how how genotypes and phenotypes work for recessive alleles. Homosexual genes will continue to live on and propagate in heterosexuals so long as they aren't eliminated by the gene therapy as seen in sci-fi horror/suspense Hollywood films.
It doesn't require a homosexual parent to have a homosexual kid.
'But that's not how how genotypes and phenotypes work for recessive alleles.'
Recessive alleles aren't immune to natural selection. It's just harder to purge them because they get exposed as phenotypes less often. As they become rarer and rarer (it'll manifest as a phenotype as the square of its frequency), selection weakens. Homosexuality, however, is common enough and the fitness penalty large enough that any recessives are exposed to a lot of selection, so it should be disappearing fast, but it isn't, which raises a lot of questions of what exactly causes homosexuality.
But if the individuals who have the greatest expression or concentration of these genes are having children less frequently (because they are no longer pressured into having children by their relatives/community), then this will act as a siphon for those genes over many generations. That doesn't mean that they will completely disappear, but that these genes would become much less prevalent.
cjslep|9 years ago
It doesn't require a homosexual parent to have a homosexual kid.
gwern|9 years ago
Recessive alleles aren't immune to natural selection. It's just harder to purge them because they get exposed as phenotypes less often. As they become rarer and rarer (it'll manifest as a phenotype as the square of its frequency), selection weakens. Homosexuality, however, is common enough and the fitness penalty large enough that any recessives are exposed to a lot of selection, so it should be disappearing fast, but it isn't, which raises a lot of questions of what exactly causes homosexuality.
toasterlovin|9 years ago