The age at menarche and first intercourse was analyzed from data obtained from a questionnaire sent to 1500 17 year-old randomly selected Danish women (76% responded). The average age at menarche was 13.37 years (SD: 1.24). The median age at the time of the first intercourse was 16.6 years. Late sexual debut was observed for girls who were relatively old at menarche and for those with a higher level of education. Apparently the age at menarche and at first sexual intercourse has not changed significantly in recent years.