Young people today come of age in a cultural and economic milieu that prolongs their attainment of the traditional markers of adulthood. Their subjective conceptions of the transition to adulthood depart radically from the traditional conception, with its emphasis on discrete transition events (e.g., marriage and entry into the workforce). Instead, the modern transition to adulthood is a gradual process consisting of the acquisition of general capabilities, rather than the achievement of externally constructed events. The state-established age of legal majority stands in marked contrast to this gradual and prolonged process. Thus, the legal construction of adulthood is starkly at odds with its social and cultural constructions. This chapter argues that abandoning the presumptive age of legal majority in favor of context-specific rules advances the state's liberty-respecting ends and better aligns the legal and sociocultural constructions of adulthood. The developmental and behavioral sciences can and ought to supplement more traditional policymaking considerations.