Zoologists have reckoned there are up to at least 750 species of animal that have been observed exhibiting same-sex behaviour, or gender role transformation (which is very common in a wide range of fauna). There is only one species on earth, however, which has exhibited homophobia or transphobia. And that is the species homo sapiens sapiens. Us. So let's not allow the foolish, ignorant or bigoted ever to use words like "natural."