[ben_w]

There's a thing called a "gene drive", which I don't really understand, but it is claimed to get around that.

https://en.wikipedia.org/wiki/Gene_drive

The toy model of this that fits in my head, is the prisoners' dilemma as a gene: every generation has a local preference for that gene, but overall it destroys that population.

Ages ago now, and I think it's been debunked anyway, people were looking for a "gay gene" and wondering how it might remain in a population; one suggestion was that it would cause hypersexual andro-philia, making both men and women with that gene very much more into guys than normal — if that actually existed in that particular form, then (modulo both contraceptives for the women, and sperm banks for gay men who want to start a family) it would count as such.