Sexual roles tend to be fixed by most societies, but in different ways. Most 'western' industrialized countries do not accept homosexuality, whereas it is tolerated in Asia and among certain primitive tribes. Discrimination between the roles of men and women exists everywhere but is somewhat more liberal in certain industrialized countries.
Since gender is the primary source of inequality, the disappearance of gender is a prerequisite for the complete development of non-sexist, fully human theory of justice. The allocation of fixed sexual roles includes general discrimination against women, against men, and the non-acceptance of homosexuality. In some cultures celibacy and the unmarried state are made virtually impossible and marriages are forced, under the influence of a societal demand for procreation. Childlessness is considered a curse.
Owing to a lack of complete scientific investigation, a differential psychology for males versus females remains to be elaborated. Despite substantial prejudice to the contrary, however, there is already a considerable amount of empirical and theoretical observations which assist in a probabilistic approach to role performance optimization for the sexes. More knowledge will enhance the preferential sex for some roles, as well as obliterate the need for specification in others.