Sexual behaviour of Cape Town high-school students.

OBJECTIVES To document prevalence rates for selected aspects of sexual behaviour among Cape Town high-school students and to conduct a survival analysis of age at first intercourse. DESIGN Cross-sectional survey. SETTING State high schools in Cape Town. SUBJECTS A multistage cluster sample of 2,740 grade 8 and 11 students at 39 schools. OUTCOME MEASURES Ever having had sexual intercourse; for those who had, age at first intercourse, number of partners during the previous 12 months, time since last intercourse; and, at last intercourse, whether the partner had been known for more than 7 days, whether any method was used to prevent pregnancy or disease, and (if so) what was used. RESULTS Overall, 29.9% had participated in sexual intercourse, with a higher proportion among males and those in grade 11. By the age of 14 years, 23.4% of males and 5.5% of females had participated in sexual intercourse. By the age of 19 years, these proportions were 71.8% and 58.2% respectively. The median time since last intercourse was 4 weeks, the median number of partners in the past year was 1, and 78.4% had known their most recent partner for more than 7 days. At their last coital episode, 65.4% had used contraception, and the most common methods were condoms and injectable steroids, which were used by 67.7% and 43.2% respectively. CONCLUSIONS The proportion of sexually active students has increased since 1990. Intervention programmes should commence in primary school. Large numbers of students are at risk for pregnancy and sexually transmitted infections.