Anthropologists are coming to recognize that the emergence of the human kinship system may be as responsible as any physiological mutation for the evolution of Homo sapiens. The basic foundations of human kinship can be divided into two types: those that are inherited from the primate, mammalian, vertebrate, animal ancestors, and those that are peculiar to the human lineage. Kinship rules generated by the unique logic of the human species' emergence can be at stark variance with our more general but still deeply embedded mammalian and primate inheritance of emotions and drives. Hence we have adultery, young lovers tragically separated, sexual violence, suicide, inheritance fraud, intergenerational conflict, infanticide, patricide, oppression of women, sado-masochism, fetishism, sexual addiction, neurosis, bloodfeuds, and so on. The most important element that the human kinship system adds to the default higher-mammal system is a new competition—between blood relationships and affinal relationships—in other words, in-law problems, a subject of compelling interest to epic.