For most religious people, the words God and sex never go together. God is conceived of as holy, pure, sexless, and as morally above the raw desires that so powerfully beset us. Sex, on the other hand, is conceived of as earthy and unholy, something we must snatch, and not without guilt, from the gods. Christianity has struggled mightily with sex; so too have most other religions. And yet when we look at sexual desire...