A critique of the possibility of genetic inheritance of homosexual orientation.

Many workers in human sexuality have tried to discover causes of sexual orientation. No one theory has proved to be satisfactory. Studies of monozygotic and dizygotic twins, some of whom have been reared separately and some together, suggest that there may be an inherited component of homosexuality. Other studies, particularly those concerned with the evolution of human sexuality, question such a possibility. A further question arises because a large part of the human population is neither exclusively homosexual nor exclusively heterosexual. This paper will examine the evidence for genetic inheritance presented by twin and family studies. It will explore ways in which a gene favoring a homosexual orientation but not reproduction could continue to exist in a population. The importance of defining terms that refer to sexual orientation will be discussed in the context of determining exactly what may be inherited. Finally, the effects of accepting genetic inheritance as the cause of sexual orientation will be discussed.