 Similarly, Nietzsche contrasts 19th-century European morality to that of pre-Christian Greek civilization.Because sex is, in Nietzsche's thought, a fundamental affirmation of life, for its being the very process by which human life is created, Christianity's elevation of chastity (including, for example, the story of Mary's virginal pregnancy) is counter to the natural instincts of humanity, and therefore a contradiction of "natural values".Nietzsche's enthusiasm for what he called "transvaluation" stemmed from his contempt for Christianity and the entirety of the moral system that flowed from it