Three clinical trials in Africa found that adult male circumcision reduced the risk of men acquiring HIV infection from heterosexual sex by 51-60%. While adult male circumcision may also have a role to play in preventing HIV transmission in the US ... the extent of this role on a population basis is unknown.Oh really? Maybe circumcision could help form keratocytes around the glans of penis but I still don't believe that would help a lot. Some scientists believe that HIV in semen(sperma) is extremely virulent, hence the main way of spreading the virus. Some others, as an assistant told me in my first year, human immunodeficiency virus (HIV) uses macrophages located in the area of the genital organs as "trojan horses" during sexual intercourse. Remember how Greeks got into Troy? Somehow similar happens with HIV and our macrophages. They're also the depot (reservoir) of the infectious agent that transport it further to lymphocytes, thus spreading the virus.
Macrophages are infected early during HIV infection and are thought to play the role of a Trojan horse by spreading infection in tissues... Infected macrophages are a reservoir for HIV and modulate apoptosis of T cells present in their vicinity.There could be some truth here, but the other method which might create an HIV vaccine, is much more efficient, although it would take a looong time to process it.