This article argues that theories that take rights as fundamental and those that take obligations as fundamental are not equivalent. The two kinds of theory differ in scope, and do so in ways that have important implications for children. The author writes that a constructivist account of obligations has theoretical advantages which constructivist accounts of rights lack, although rights-based approaches sometimes have political advantages which obligation-based approaches do not. Finally, the article concludes that in the specific case of children, taking rights as fundamental has political costs rather than advantages and that taking rights as fundamental in ethical deliberation about children has neither theoretical nor political advantages. The author suggests how we could obtain a more direct, perspicuous and complete view of ethical aspects of children’s lives by taking obligations as fundamental.