In the developing world, the virus has existed for at least 65 years because HIV is rarely spread heterosexually. Research that studied the wives of infected hemophiliacs showed that an HIV-positive person requires over 1,000 unprotected sexual contacts with an HIV-negative person from the opposite sex to pass along the virus just once. In another surprise study, published in the Lancet, 1997, 349:851-2, French doctors at the Cochin-Port Royal hospital in Paris looked at the risk of […]