Abstract
HIV sexual transmission via the male genital tract remains poorly defined. Male circumcision was shown to reduce female-to-male transmission in Africa, providing a clue that the foreskin plays a role in the route of transmission. Scientific data in four categories relating to how the foreskin might affect HIV transmission is summarized: (i) surface area, (ii) microbiologic environment, (iii) HIV-1-susceptible cells, and (iv) tissue structure. The relative contribution of each of these areas is yet unknown, and further studies will be crucial in understanding how male circumcision affects HIV transmission in men.