While numerous studies have explored young people's sexual behaviour in Peru, to date few have explored how adolescents situate sexuality within the context of their broader lives. This information is needed to inform policies and programmes. Life history interviews were conducted with 20 12-17-year-old young women and men from a low-income settlement near Lima, Peru. Data were analysed using holistic content analysis and grounded theory. Sexuality had a strong presence in respondents' lives. However, interviewees viewed the full expression of their sexuality as a constrained choice. Particular constraints derive from the belief that sexual intercourse always results in pregnancy; the nature of sex education; the provision of proscriptive advice; and the family tensions, economic problems, racism and violence present in young people's lives. The results of this study can inform policies and programmes to support young people as they make sexuality-related decisions. © 2010 Taylor & Francis.