Sexuality is not an immutable fact, but a set of representations, practices and norms that are learned and transformed throughout life. This learning process, as well as the way in which individuals construct different categories of sexuality, differs according to their gender, sexual orientation, socio-economic background, or their specific life experiences (whether they have discussed sexuality with their family, whether they have been subjected to violence, etc.). What forms does this process of learning about sexuality take? Based on a mixed method survey, including statistical analysis of data from the survey on the affective lives of young people (Enquête Envie, Ined 2022-2023) and retrospective interviews with adults aged from 18 to 30, this dissertation looks at how individuals learn to categorize certain practices as belonging (or not) to sexuality, as well as the social variations surrounding these learning processes and the construction of sexual reflexivity.