African nations have the youngest populations on Earth, with 40 percent of the continent’s population under 15 years of age. A population explosion is unfolding, predicted to more than double the number of Africans by 2050, topping billion people. A youthful population is adventuristic, risk-taking, and vibrant — but also dangerously self-destructive. The very activities that put people at risk for acquiring HIV are inherently elements of an urbanizing, sexually active youth-dominated milieu. Most of the million people living today with HIV reside in southern and eastern Africa. If those now receiving daily anti-HIV drugs are no longer able to access treatment, they will swiftly become infectious to their partners.