Sexual intercourse remains taboo among adolescents in a Chinese society such as Hong Kong. It is not openly discussed and little research has been done on its impact on health, although it carries serious risks of contracting sexually transmitted diseases (STDs)/HIV. In 1999, a cross-sectional, self-report survey on youth risk behaviors was carried out on 8382 students 15-18 years of age from 48 schools in Hong Kong. Three hundred seventy-seven (4.69%) reported that they had had sexual intercourse. Among them, forced sex (16.94%) was common, most often happening to boys (52.38%). They were more likely to have consulted doctors in the last month (odds ration [OR] 1.41 in boys 95% confidence interval [CI] 1.03, 1.94; OR 2.46 in girls 95% CI 1.81, 3.30) and 6 months (OR 1.33 in boys 95% CI 0.98, 1.78; OR 2.66 in girls 95% CI 1.80, 3.91). They also perceived poorer and deteriorating health. The sexually active female students were 6.70 times (95% CI 4.65, 9.66) more likely to attempt suicide than the other group and were more likely to take sick leaves (OR 3.56 in girls 95% CI 2.35, 5.41). Parental education and occupation, place of birth, and type of housing did not correlate in the initiation of sexual intercourse. The sexually experienced group reported worse physical and psychological health as well as health perception. Some of the characteristics and patterns identified in our study were quite different from the findings in the West but further studies are required to determine the reason for this.