Surely few things in this world are more mysterious than sex. Surely few things give such clear evidence that there must be more to them than the sum of their parts. On one level, sex is a simple biological function that exists to populate the earth with human beings. On the other level, it is so much more than a biological function, for how else can we explain the longing for it and the pleasure of it, the shame of its misuse and the agony of its abuse? How else can we explain the righteous jealousy with which we guard it or humanity’s obsession with expressing it in anything other than the way God explicitly commands?