Freud said that incest provokes horror because it touches upon our forbidden, ambivalent emotions towards members of our close family. There is little doubt that incest has nothing to do with genetic considerations. In today's world incest does not need to result in pregnancy and the transmission of genetic material. Good contraceptives should, therefore, encourage bad, incestuous, couples. The more primitive the society, the more strict and elaborate the set of incest prohibitions and the fiercer the reactions of society to its violation.
Incest seems to interfere with well-established and rigid patterns of inheritance.
This interference led, in all probability, to disputes. In more primitive societies, arms were resorted to in an effort to resolve conflicts. To prevent recurrent and costly bloodshed was one of the intentions of the incest taboo. The incest taboo is, therefore, a cultural trait. Protective of the efficient mechanism of the family, society sought to minimize disruption to its activities and to the clear flows of authority, responsibilities, material wealth and information horizontally and vertically.