Seems to me, from an evolutionary standpoint, that homosexuality is a dead end. How do genes get "enhanced" if they're not passed on through reproduction?
Part of the theory of evolution is the concept of ‘group’ of ‘collective’ fitness.’
The evolutionary researcher looks at a given behavior and tries to fit it into some kind of advantage. Usually he attempts to show an advantage to the individual in the sense of increasing that individual’s progeny.
However, when he can’t find an advantage to the individual, he looks for an advantage to the group, or even the entire species.
‘Altruism,’ whatever one takes that to mean, is the number one type of behavior that evolutionary researchers seek to explain with their group fitness theories.