Homosexuality, in and of itself, does not nothing to harm anybody. Incest has the potential to bring costly (in a medical sense) children into society. If I had to choose one to be unacceptable, it would be incest, for that reason.
Personally, I don't really care who people have sex with, as long as it isn't rape and it isn't someone I am sleeping with doing something that I don't personally care for or could make me ill (literally).
Personally, I don't really care who people have sex with, as long as it isn't rape and it isn't someone I am sleeping with doing something that I don't personally care for or could make me ill (literally).