[CORed]

I think your point about there being a spectrum between hetero and homo is valid.

As far as the hypothetical "homosexuality gene" not being selected out, it may be something like a lethal recessive. It takes a long time for lethal recessives to be selected out because they are only lethal if an individual is homozygous for the lethal version (both copies of the gene are the lethal version). Also, it turns out that some lethal recessives have survival value for individuals who are heterozygous (one copy is the lethal version, one copy is the normal version). For example, the sickle cell gene: Heterozyougs individuals are more resistant to Malaria. Cystic fibrosis: heterozygous individuals are more resistant to water-borne diahreal diseases.

What the survival value of the hypothetical gay gene might be for heterozyogous heterosexuals (that's a mouth full) might be is anybody's guess. Maybe better fashion sense helps them attract women. Maybe they keep their living quarters cleaner while single, and are less likely to succumb to bacterial infections before they have children.