Lev 18:22 Do not have sexual relations with a man as one does with a woman; that is detestable.Interestingly enough, this instruction is presented only to humans, all other animals are free to love any other animal no matter whether they are male or female.
I've been told, over my lifetime that "homosexuality is a human aberration, and that no other animals indulge in homosexual encounters." This is not true: Wikipedia gives a comprehensive list of animals known to display homosexual behaviour.
This is interesting to me, because on Saturday afternoon I witnessed some of this behaviour in the monkeys outside my kitchen window.
I watched him interact with another male. He was very obviously sexually aroused, so his interest was not merely friendliness or a request for grooming. He approached the other male with an act which surprised me: he kissed him on the mouth. The other male backed off, without returning the kiss or encouraging a further approach.
The aggressive male tried again, and then again, but then realising the other male wasn't interested, or perhaps realising his mistake (I'm prepared to admit it might have been that he merely realised the other monkey was male), he backed off and went on to approach one of the females.
Now, while I'm prepared to concede that the monkey could have been mistaken in approaching what he thought was a female, I also can't believe that because surely, as the leader of the troop, he would know all the members, and their gender. So I'm prepared to accept that he was happy to engage in homosexual sex. But also, another thing I found interesting was that he accepted the rebuff, without pressing his advance. It seems that monkeys don't rape each other. Well not in this family anyway.
As for the kissing... that fascinated me because I truly believed that kissing was a cultural thing exclusive to humans.