A favourite argument used by the religious right against homoerotic relationships, and by the Vatican theologians against any form of sexual expression outside of marriage and not open to making babies, is that such sexual activities are "against nature", and that the "purpose" of sex is procreation. Well, the people making these claims have never considered the actual evidence from, well, you know - "Nature" itself, which shows the exact opposite. In a famous exchange, Anita Bryant once remarked that the things that homosexuals do were so disgusting that "even barnyard animals wouldn't do it." When it was pointed out to her that actually, barnyard and other animals do "do it", as is well known to farmers, she simply replied, "Well that still don't make it right". No, and it don't make it wrong, either. On sexual ethics, "Nature" is morally neutral.
"Anita Bryant, Reality Denier"