Differential risk theory as a subset of social exchange theory: implications for making gay marriage culturally normative and for understanding stigma against homosexuals.

Differential risk theory, a subset of social exchange and equity theories, is proposed as an explanation for stigma towards homosexuals and as a basis for normative preferences for heterosexual marriage. Numerous gender differences involved in long-term relationships require members of such close relationships to assume greater interpersonal and social risks and thus costs, compared to same-gender relationships. Without compensating rewards or reduced costs, heterosexual relationships would be unfairly disadvantaged. Resistance to making gay marriage normative and/or equivalent legally to heterosexual marriage may be traced, rather than to homophobia, to societal attempts to maintain equity between classes of relationships characterized by inherent differential risks.