This paper explores the role of sex and relationship education (SRE) in reducing teenage pregnancy rates. It critically examines some of the assumptions underlying the emphasis placed on SRE within the teenage pregnancy strategy ( SEU, 1999)--in particular, the view that ignorance of sexual matters plays a key part in teenage conception. An analysis of these assumptions is used to explore the reasons why the research evidence on the efficacy of sex education in changing adolescent sexual behaviour is mixed. Attention is drawn to the wider contexts within which adolescent sexual behaviour occurs--and the wider contexts within which schools are operating to provide SRE. Also highlighted are suggestions from the literature about what young people want from sex education and the possible implications for reducing teenage pregnancy. The paper concludes that although important, SRE, on its own, is unlikely to be the panacea sought by politicians to reduce the incidence of teenage pregnancy in the United Kingdom.