The article presents the analysis of two web sites, the French one 'Info-Ado' (SIHCUS-CMCO, Strasbourg) and the Italian 'Ti amo in un click / I love you by a click' (Consultorio Giovani di Feltre, Venetia), both devoted to preadolescents' and adolescents' sexuality and reproductive health. This analisys enables us to explore 9-13 aged children's questions, worries, uncertainties about their body in transition. These tweens denied any inscription in 'preadolescence' as a bound age category; their speech is about daily embodiment of bodily changes.