 “Healthy children, healthy nations.” For who’s health to discipline reproductive bodies? 
Research Framework: Based on a sociological and gender-analysis theoretical and conceptual framework, this article studies the promotion of a recent international health program dedicated to women and children whose scientific arguments rely on the domain of epigenetics. It would be now possible, through early intervention on the (nutritional) environment of individuals during conceptional and periconceptional periods (pregnancy and the first two years of life), to prevent the emergence of chronic pathologies in adult life. Objectives: The aim is to provide a history of this biopolitics (Foucault, 2004) and to describe its process of legitimization, so as to question consecutive social stakes related to new norms and injunctions on (healthy) children production. Methodology: To that end, we implement a methodology combining scientific and grey literature review, ethnography of the 1,000 Days US ONG and semi-structured interviews with international experts (WHO, USAID, Unicef, Sun). Results: We show that this program contributes to the building of a deeply unequal morality firstly drawing on a medical promise but also basically leaning on an economic promise : a healthier body would both guarantee the productivity of children (then perceived as adults to become) and sound finances of (global north) Nations. Conclusions: Besides its focus on the health of both young children and Nations, the program also leads to the training of gestating bodies, and especially subaltern women’s bodies : obese, racialized, sick or poor. Contribution: This article demonstrates the scientific contribution of social sciences and gender studies to medical research on children's health as well as their transformations into politics.