Young people, also known as teens, pre-teens or young adults, constitute an unstable category, which whom those associated with the documentary languages of indexing and book publishing undertake to define, particularly through their reading practices. This crossover study of documentary discourse (in this case, RAMEAU and CLIL classification) and publishing professionals allows us to trace the conceptual contours of the adolescent, and to question social, gender and literary genres. Ultimately, a gendered marking can be observed, both in the definition of the term’s identity, as well as in the publishers’ catalogues of children and young adult literature.