The Gay Animal Kingdom
It's not actually very gay, well, it is and it isn't, but it radically critiques the narrow-minded Darwinian fixation on sex with breeding. Other animals use sex for fun, social bonding, and fun, and do not separate into gay and straight animals. They've all got pleasure neurons in their genitals, and their behaviour is not neurotically reproductive, much as the Papists (and other word-worshipping power-mongers) may be horrified at this wanton wastefulness in the wild. Non-breeders and non-breeding sexual behaviours are part of the social mix, too, and an essential part, contrary to the agrarian mindset resentful of having wasted food on a gay bull or whatever their problem is.
I like that the research was instituted by a transgender scientist, whose personal sitaation gave her a broader perspective that the standard binary fixation.
Anyway, have a read, broaden your mind, and grow beyond the seedy fixations of the anti-natural fun police.