 Like these radical feminists, some socialist-feminists have tried to develop a “dual systems” theory (cf. Young 1981). This involves theorizing a separate system of work relations that organizes and directs human sexuality, nurturance, affection and biological reproduction. Rather than seeing this as an unchanging universal base for patriarchy, however, they have argued that this system, thought of as the “sex/gender system” (Rubin 1975; Hartmann 1978, 1981a,b), or as “sex/affective production” (Ferguson 1989, 1991; Ferguson and Folbre 1981) has different historical modes, just as Marx argued that economies do. Rubin argues that sex/gender systems have been based in different kinship arrangements, most of which have supported the exchange of women by men in marriage, and hence have supported male domination and compulsory heterosexuality. She is hopeful that since capitalism shifted the organization of the economy from kinship to commodity production, the power of fathers and husbands over daughters and wives, and the ability to enforce heterosexuality, will continue to decline, and women’s increasing ability to be economically independent will lead to women’s liberation and equality with men.