How do you know what is 'normal'? Ten percent of the population is homosexual. Animals engage in same sex sexual activity. Prove, other than what your religion says, that homosexual behavior is not 'normal.' Empirically, with solid, indisputable, scientific evidence.
I have never understood what other animals are supposed to have to do with anything in this discussion. Earthworms are hermaphrodites; does that make hermaphroditism normal for humans? Lizards can regenerate their tails if they lose them; does that mean humans can regenerate body parts? Lions live in prides with one male and bunch of females; while I'm sure there are human men who would LOVE that arrangement, does it make that normal social behavior for human beings?
Seems to me the whole point of identifying thousands of different species is that they're
different. To try to say, "THIS species does this, therefore that is right and normal (in a scientific sense) for all species" is ridiculous. And even those few species constantly touted by activists as exhibiting "homosexual behavior" only do so rarely, and under specific biological imperatives related to species survival. I don't believe anyone has yet identified any specific reason that the human species would require such a biological imperative. To put it bluntly, homosexual behavior in humans is of any use, scientifically speaking, to the species as a whole.