A girl's first sexual intercourse is often unplanned and may put her at risk of STDs and HIV infection as well as unwanted pregnancy. The high prevalence of HIV among 15-24 year olds in KwaZulu Natal suggests that sex is initiated at an early age. This paper is based on a 1999 survey in South Africa which identified age of sexual debut and childbearing among adolescent girls in KwaZulu Natal. Of a sample of 796 girls, almost half had already had first sexual intercourse at a mean age of 16. Of these, 44 per cent reported having communicated with their first partner about preventing pregnancy, of whom 36 per cent were able to use a contraceptive method. The majority used a male condom, the pill or injectable. Similarly, 30 per cent had used a method, almost all of them a male condom, to prevent a sexually transmitted disease at first sex. About half of the girls had ever been pregnant and a large percentage of these indicated that the pregnancy had been unwanted. If sexuality education were to begin before puberty, at age 9-10 and in primary school, then many more girls would be in a better position to make informed choices about their sexual activities by the time they begin to engage in sex or reach menarche.