In the beginning, say the Dogon, there was a maternal world egg that was shaken by seven huge movements of the unformed universe, which caused the egg to break into two placentas, the egg having been fertilized by the creator, Amma. Each placenta contained a set of twins, in both cases one a male, one a female, although all four of the children contained both the male and female essence. The twins are called the Nummo. One of the male twins, named Yoruga, broke out of a placenta prematurely, and the piece of the sac from which he broke out became the earth. Yoruga tried to get back into his sac to reunite with his twin, but she had deserted their placenta for that of the other set of twins. So Yoruga descended to the earth and attempted to copulate with it, but no children resulted from that act. Amma sent the other occupants of the placentas down to earth to see what they could do about creating humans. It was the intercourse between these brothers, sisters, and cousins that led to the creation of humans. Because all humans are descended from these original twins, all humans are descendants of incestuous relations between a mother and her twin brother or a father and his twin sister. In the complexity of Dogon religion and mythology, then, brothers and sisters are considered “parents” of each other’s children. All of this suggests a peculiar kinship system. In Dogon tradition, a man will, if possible, marry a first cousin fathered by his maternal uncle.