AbstractThe marginalisation of children globally is frequently justified by appeal to medical, developmental science. While childhood has increasingly become recognised as a social construct, this research has focused largely on education and legal structures, leaving this medicalisation unexamined. This essay closes that gap by examining the medicalisation of childhood and the contribution of the medical system to adult power. These are approached in separate sections. The first portion of this essay addresses the theoretical and rhetorical manner in which children are medicalised, using Piaget's theories as examples of a trend to over‐state the universality of childhood deficiencies and assume adult competences. Latour's work on the scientific black‐box is combined with Halliday's assessment of scientific language to examine how these theories are transformed from specific psychological findings, into assumed objective truths, carrying disenfranchising assumptions about children into public discourse. The essay's second part examines the practical role of the medical system in mobilising adultist discourses and disempowering children, through the operation of scientific management. This is built up from discussions of childbirth and adolescence to wider issues of medical power as it permeates educational, legislative and media spaces through Samuel's concept of biocertification. Finally, these two parts meet in highlighting the role of medicalisation in maintaining the hegemony of adult power through its veil of objectivity and expansive reach. I contend anthropological works referenced throughout the essay show that medicalised narratives of childhood are insufficient but culturally contingent and thus open to revision.