This article traces the shifts in the conception and delivery of sex education in British schools during the 1990s, drawing upon policy documents, teaching handbooks and teachers’ schemes of work. Two distinctive forms of sex education emerged during this period: a mandatory sex education focussed on the risks of HIV/AIDS and, later, teenage pregnancy; and a non-curricular sex education based on a discourse of emotional wellbeing and personal development. Far from being mutually exclusive, these two forms of education have, in recent years, started to overlap. Mastering a certain style of emotional expression is regularly framed as a means of avoiding ‘high risk’ sexual encounters and teenage sex is often described as damaging one's emotional wellbeing. The article offers a critique of these developments, arguing that current Sex and Relationship Education prescribes a certain emotional disposition, mystifies sex for young people, and transforms teenage pregnancy and sexually transmitted infections into problems of emotional maturity.