In almost all cultures, incest is viewed as the ultimate tabu that, according to Claude Levi-Strauss, is at the foundation of human culture itself. Incest has been the subject of intensive scrutiny and theorizing by anthropologists, and there are varying ideas on why the tabu, which is virtually universal, arose. A number of creation myths resort to incestuous peopling of the earth for purely pragmatic reasons. An account from the Indian Brihadaranyaka-Upanishad tells of an androgynous and incestuous pairing that is viewed more equivocally. Classical mythology, of course, does not shy away from tales of incestuous relations. In "The Incest of Wenebojo's Grandparents," a sister sleeps with her brother at night without his knowledge. Many stories about father-daughter incest find ways to diminish the father's guilt, while others eliminate his culpability altogether. The most famous story of mother-son incest is that of Oedipus, told in bits and pieces by many ancient writers.