This study moves in the space between two fields: science and technology studies (STS) and childhood studies; it thus belongs to the broader STS literature that investigates everyday practices outside the laboratory. The interpretation of ethnographic and bibliographic data on contemporary cardiovascular and obesity prevention in German kindergartens makes evident that when knowledge travels from biomedical laboratories to the preschool, then psychology comes into play! Bodies of knowledge such as behavioural or cognitive theories shape prevention and intervention practices, which could be seen as originally resulting from biomedical findings and trends. Accompanying this development is a change in the primary sciences that deal with childhood: these are no longer pedagogy or developmental and educational psychology (at least in their traditional forms), but "developmental science". All this shapes contemporary childhood in quite normative ways. It thus remains an open question what non- or less normative institutional practices and bodies of knowledge could look like. (Contains 11 notes and 1 figure.)