Why are you assuming a reproductive purpose on sex? Are you comparing humans to animals, or enforcing people to have kids?
That is like asking, "Why are you assuming a digestive purpose on eating?" Sex is for the purposes of reproduction - that's just fact. Keep your strawmans to yourself.
One thing human development has achieve is to split sex from reproduction. Humans will have sex for fun, it's human nature. You cannot go against it, religions have failed.
That doesn't change what nature's intent for your organs is. You are free to engage in crimes against nature, but don't try to convince people its "normal".
Natural selection IS nature, you can't go against it unless you like eugenesia and reducing genetic pool. Again: crime is a moral judgement, not science.
Homosexuality has been always present in nature. It has a evolutionary advantage (paradox) because it has not been discarded by natural selection.
Your premise fails basic logic. Homosexuality is discarded by natural selection by definition - it doesn't end in reproduction.
If homosexuality is discarded by natural selection, why it still exist? Are you assuming a Mendelian inheritance of homosexuality?
"If homosexuality is discarded by natural selection, why it still exist? " I'm sure non-stop promotion in the media helps. Literally every TV show has gay character by the 2nd season.
Illnesses have been always present in nature. Contracting them is certainly not an advantage since your genes are being removed from the genpool (inability to procreate).
