The Incest Controversy

Abstract

Natural selection theory may provide the basis for resolving the controversy which revolves around the role played by genetic and cultural determinants of incest and the frequency with which it is committed. Adaptive inbreeding avoidance mechanisms have been persistently selected for in evolution. The mechanisms have been quite diverse and many of them would not serve to reduce human incest. However, one determinant, early and intimate association, which has been established as an inhibitor of sexual attraction in birds and mammals, appears to play the same role in our species. Elaboration of incest rules to include other relatives is a product of man's cognitive capacities. The degree to which these rules are followed is closely related to their congruence with sound reproductive strategies. Sexual attraction between consanguineous human beings is probably determined by at least six complementary factors. The common nuclear family phenotype, lack of sexual attraction for one another, is a function of a normal genetic endowment interacting with a normal environment.