 Assumptions about well-being, tacit as well as explicit, pervade our thinking about disability. Decisions about abortion after a “positive” prenatal test result are often based on the parents’ judgment about the child’s expected quality of life. Decisions about life-sustaining treatment for severely disabled infants and critically ill adults are often made on the same basis, although what counts now as an acceptable quality of life may differ from what is considered acceptable when contemplating the futures of fetuses and newborns. Judgments of well-being also figure in allocation decisions, where scarce resources may be diverted away from persons who, because of certain disabilities, are deemed to have poor prospects for an acceptable quality of life, and toward persons with “better” prospects. The examples could be multiplied, and they are not confined to health-related matters.