Risky sexual behaviour is a key strand in ALSPAC's newly funded ESRC programme. Sexual behaviour is a part of normal human development. Although early sexual activity has adverse outcomes, including unwanted pregnancy, sexually transmitted infections including HIV, and psychological disturbances, the vast majority of adolescents do not experience these consequences. Investigating the origins of risky behaviour should therefore take place within the overall context of the development of romantic and sexual behaviours. Developmental theories suggest a number of potential risk factors for early sexual behaviours but these hypotheses have not been tested extensively in large prospective studies.

Data about romantic and sexual behaviours have been collected by computer assisted self interview in ALSPAC since age 11+. The questionnaire was adapted from the Adolescent Sexual Activity Index. This instrument asks a child about their participation in a hierarchy of ten romantic and sexual activities, and has additional questions about the context of encounters.

Preliminary analyses at 11+ and 12+ clinics have included data from 6856/7218 (95%) children aged 11-12 years and 6801/7011 (97%) aged 12-13 years. Amongst 11-12 year olds 16.2% (95% CI 15.3-17.1) had kissed another person. One year later, 32.6, 95% (CI 31.5-33.8) had kissed another person. More intimate behaviours (asked only at 12+) were much less frequent. For girls and boys combined, 11.8% (95% CI 11.0-12.6) of 12-13 year olds had lain down together with someone of the opposite sex and 4.9% (95%CI 4.5-5.5) reported petting or coital behavior of some sort. No analyses of factors associated with these behaviours has yet been done.

Objectives

1. To document trajectories of romantic and sexual development in 11-13 year old children;

2. To determine indicators of social position, family and neighbourhood environment, parental and child behaviours in early and middle childhood that are associated with the early onset of intimate sexual behaviour in 11-13 year olds;