 Disability is often initially encountered as an atypical mental or physical condition whose impact on well-being is mediated by the physical and social environments. For example, an individual is deciding whether to undertake expensive and risky surgery to restore functioning lost in an accident; a couple is deciding whether to continue a pregnancy with a fetus diagnosed with a genetically-based health condition; a legislature is deciding how much money to allocate to competing injury-prevention programs. All these decision makers first confront disability as a biological phenomenon—a sudden or gradual loss of functioning; a genetic condition with various health effects; a range of vehicular, recreational, household, and workplace injuries. Their concern is with the effect of disability, encountered this way, on lives they care about or are charged with protecting: their own, their future children’s, or their constituents’.