Queer Theory emphasizes radical differences from social norms and views social structures as the root of human oppression. It focuses on critiquing social boundaries and the mechanisms that enforce them. Historically centered on sexuality studies, Queer Theory also addresses other issues and is critical of anything mainstream. While marriage equality seems radical to some, Queer approaches tend to oppose gay marriage as too traditional and conforming to social control. Queer Theory draws from both academic social science and political activism that challenges traditions and institutions. It overlaps with but also differs from feminism and racial theory by questioning the validity of gender and racial categories.