Abstract
Previous research on child/teenage sexual experiences has largely focussed on negative outcomes such as teen pregnancy or acquiring sexually transmitted infections and are mainly cross-sectional. Longitudinal research is required to assess normal sexual development and the attainment of psychologically healthy attitudes towards sexuality. The Avon Longitudinal Study of Parents and Children (ALSPAC) has administered questions on relationships and sexual experiences from the age of 11 years to the index children. This data note describes these data.