| Men | Women | ||
| Number resident in ACDSA on 1 January 2003 aged 12–25 years | 10089 | 10469 | |
| Number who participated in at least one sexual behaviour survey during 2003–7 (% of number resident) | 6728 (67%) | 7917 (76%) | |
| Ever had sex | |||
| Yes | 3625 | 5038 | |
| No | 2849 | 2664 | |
| Missing | 254 | 215 | |
| Number whose sexual debut was before the start of the observation period (total, %)* | 2345 (6374; 37%) | 2924 (7648; 38%) | |
| Median (IQR) age (years) of those who had already sexually debuted | 19.7 (18.0–21.8) | 20.8 (19.1–22.8) | |
| Analysis population: number who had not already sexually debuted by the start of the observation period | 4029 | 4724 |
ACDSA, Africa Centre Demographic Surveillance Area; IQR, interquartile range.
*AFS was missing for 48 women (1%) and 95 men (3%); 6 other women and 5 men were excluded because their AFS report was higher than their age at time of interview.