Abstract: As we begin to understand the biology of aging, it will be ever more tempting to try to plan for the social consequences of the coming biomedical interventions in this arena. However, this will remain a daunting task, because the larger consequences of the arrival of antiaging interventions will greatly depend on the relative character and timing of the specific procedures that emerge. Three basic classes of interventions are likely: ones that slow aging in adults, ones that reverse aging in adults, and embryonic interventions that modify the overall trajectory of human aging. The consequences of each will differ significantly in the time required before noticeable demographic shifts begin to manifest in the human population, and in the social and political changes the interventions evoke. The specific societal consequences generally will arrive long before the demographic ones, and will hinge on the technical details of the interventions themselves—their complexity, physiological targets, modes of delivery, costs, unpleasantness, and the character and frequency of side effects.