ABSTRACT
The argument that laws that discriminate on the basis of sexual orientation in fact discriminate on the basis of sex is not new. In women's rights cases, courts have justified different treatment based on a finding of "real" difference, most often involving pregnancy. In fact, claims of sex discrimination in gay rights cases may be the only realm in which formal equality theory still has any real intellectual kick. Anti-subordination theory speaks to this: sex discrimination not only classifies, it subordinates a class. Gender-linked stereotypes about sexuality are not just about behavior. They are about what people perceive as definition, and that definition turns on the naturalness and the thoroughness of male-female difference. The sex discrimination argument has also begun to gain traction in sexual orientation cases arising under statutes. An argument that marriage can exist without sexual difference implies that gender polarity is not essential for a primary social unit.
