Continuing tensions exist between mainstream bioethics and advocates of the disability rights movement. This paper explores some of the grounds for those tensions as exemplified in From Chance to Choice: Genetics and Justice by Allen Buchanan and coauthors, a book by four prominent bioethicists that is critical of the disability rights movement. One set of factors involves the nature of disability and impairment. A second set involves presumptions regarding social values, including the importance of intelligence in relation to other human characteristics, competition as the basis of social organization, and the nature of the parent-child relationship. The authors' disapproval of certain aspects of the disability rights movement can be seen to be associated with particular positions regarding these factors. Although the authors intend to use a method of ‘broad reflective equilibrium,' we argue that their idiosyncratic commitment to particular concepts of disability and particular social values produces a narrowing of the moral significance of their conclusions regarding disability rights.