Abstract: This Article offers two main contributions to the study of sex stereotyping. First, it identifies an organizing principle that explains why some forms of sex stereotyping are today legally prohibited while others are not. Second, it argues for a shift in the current rights framework—from equal opportunity to individual liberty—that could assist courts and other legal actors to appreciate the harms of currently permissible forms of sex stereotyping. Commentators and courts have long observed that the law of sex stereotyping has many inconsistencies. For instance, it is lawful today for the state to require that unwed biological fathers, but not mothers, establish a relationship with a child as a condition for parental rights, but it is unlawful to exclude fathers from the category of “primary caregiver” for medical leave purposes. It is lawful to deny a female guard a position at an all-male prison but unlawful to refuse to hire a woman as a researcher for a physics clinic. It is lawful to post a “men only” sign on a bathroom door but unlawful to post the same sign on a courthouse door. This Article offers an organizing principle that explains these seeming inconsistencies. The main thesis is that there are today two primary branches of sex-stereotyping law: one that prohibits stereotyping and one that permits it. The prohibiting branch reflects an event in antidiscrimination law that began in the 1960s and involved integrating the private sphere of the family with the public spheres of the market and political life. This event involved three steps: (1) a new rationale regarding the harm of sex stereotyping—anti-subordination; (2) a new concept of gender—gender role; and (3) a new articulation of an equality principle—equal opportunity for women to participate in the market and for men to participate in domestic activities. These shifts produced statutes and decisions that rejected traditional division-of-labor stereotyping. In the same years, however, a parallel branch of permissible sex stereotyping flourished. This branch includes mandatory appearance codes in the workplace, schools, and prisons; denial of parental rights of unwed fathers; and sex segregation in bathrooms, locker rooms, prisons, and the military. This Article argues for a shift of focus in the law of sex stereotyping. It underscores the limits of an equal opportunity framework and argues that an individual liberty framework better captures the harms of many individuals who are today subjected to currently lawful forms of body stereotyping.