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.