The most powerful generalization about the history of reproduction posits a mid-eighteenth-century shift from the broader, premodern framework, ‘generation’, to the narrower, modern notion of ‘reproduction’. Focusing on these keywords, Raymond Williams-style, this chapter reassesses the case by examining the genesis of the standard account in François Jacob’s The Logic of Life and feminist histories of medicine, reviews resources for a richer history, and surveys usage in French, English and German. Special attention is given to early uses of ‘reproduction’; to the work of Georges-Louis Leclerc de Buffon and the physiocrat François Quesnay in the 1740s that is credited with pioneering fresh meanings of ‘reproduction’ respectively in natural history and economics, both fields concerned to increase resources; to the slow nineteenth-century takeover by ‘reproduction’ of some of the terrain of ‘generation’ and its accretion of links to copying and manufacture; and to the modern career of ‘generation’ in the sense of a cohort of the same age. This makes it possible to chart a path between two opposed views: that the concept of ‘reproduction’, established in the late eighteenth century, was already potent in the early nineteenth, and that the sciences formally recognized reproduction only in the twentieth century.