Polygamy, I don't know, could be because they wind up with pressure for very young girls to marry old men, but that's just what I've seen in the ones that make the news. Otherwise, if women choose to marry up and are ok sharing, what do I care? Incest is illegal because it produces offspring with genetic problems such as hemophilia, and though we're joking about the horse, really how do you get consent from an animal? If the animal doesn't want it, and interspecies relations are uncommon to say the least, how can you think that that sheep is ok with ol' Murphy? Then it just becomes a cruelty to animals charge.

Homosexuals, however can and often do consent. They have physical differences from straight men, namely enlargements of the hypothalamus. Are you suggesting that they choose to have enlarged hypothalami?