The politically correct answer to this question is that high HIV prevalence in heterosexual populations is due to poverty and discrimination, whereas an objective epidemiological answer is that HIV prevalence is low in most heterosexual populations because the vast majority of heterosexuals do not routinely have multiple and concurrent sex partners and the infectivity of HIV via vaginal intercourse is very low in the absence of facilitating factors.

Factors that create the conditions for a “perfect storm” of HIV/AIDS in sub-Saharan African populations include:

From 20% to 40% of sexually active males and females in many SSA countries have multiple and concurrent sex partners on a routine basis.

A high proportion of sex partner exchanges in SSA are on a weekly or monthly basis within small but overlapping sex networks or groups. The prevalence of facilitating factors that can greatly increase the risk of sexual HIV transmission is from 1 to 2 orders of magnitude higher in SSA populations compared to most other populations.

The prevalence of protective factors against sexual HIV transmission (male circumcision and condom use) , are low in most SSA populations.