The aging of the world's population is an unprecedented recent phenomenon in human history, as for millennia - at least from the Neolithic to the mid-18th century - the age structures of human populations have changed little. The question posed by this anthropological perspective seems at first sight quite simple: how did this aging come to be? We will see that from a demographic point of view, the answer seems trivial: a basic shift in population structure is at the origin. However, we will go further by exploring the historical and political conditions of this transition by mobilizing the Foucauldian notion of biopower. We argue that this notion has the heuristic advantage of linking several core processes at work in the demographic transition. Although our analysis focuses on France to illustrate the notion of biopower in Foucault's work, we also discuss several non-western societies to explain why demographic aging is inevitable across the globe due to biopower strategies and "dispositifs". This article also constitutes a reflexive analysis on our practices as gerontologists and on the widespread "successful aging" concept.