
Yeah, we're talking past each other.
Trouble is, genes aren't binary. As the article points out, genes that cause sickle cell disease also help to increase the chance of survival of malaria. The benefits of having genes that increase homosexual tendencies may have other benefits that aren't immediately apparent.
(That's one of the reasons why eugenics is not just evil, it's stupid.)
"Mental illness" is a big minefield. Just about every woman was lumped in that category at one time (and not that long ago). Dirac may have been autistic -
http://en.wikipedia.org/wiki/Paul_Dirac "Fixing" homosexuals didn't end well in at least one famous case -
http://en.wikipedia.org/wiki/Alan_Turing
Understanding changes.
The world becomes a tiny, confining place when we try to force it into boxes. Treating everyone equally, with equal benefits from - and responsibilities to - society (when possible), is the best approach.
Cheers,
Scott.