Demography and economics are linked and it is not possible to look at either discipline in complete isolation from the other. The gap between the time of first sex and first marriage is of particular importance, as this is the time when a person is most vulnerable to infection with HIV/AIDS as well as unwanted pregnancies. This gap is thus referred to as the risk gap. Both these phenomena are extremely costly. The risk gap in South Africa is growing due to the duel impact of delayed marriages and sexual encounters which take place at an increasingly early age. There is a positive relationship between the provincial HIV/AIDS prevalence rate and the provincial risk gap. This suggests that by manipulating the risk gap, government may have a tool that could be used to affect the HIV/AIDS level in South Africa.