In a potentially major breakthrough in the campaign against AIDS, French and South African researchers have apparently found that male circumcision reduces by about 70% the risk that men will contract HIV through intercourse with infected women. Other than abstinence and safer sex, almost nothing has been proved to reduce the sexual spread of HIV, the virus that causes AIDS. World-wide, the major route of HIV transmission for many years has been heterosexual sex. Vaccine developers have said they would consider an AIDS vaccine with just 30% efficacy useful. But so far, no effective vaccine against the disease has been...