At 24 months, 114 men of the men initially circumcised and 153 of the noncircumcised tested positive for H.S.V.-2. After controlling for various health and behavioral factors, the researchers estimated that circumcised men had a 25 percent reduced risk of infection. The results do not apply to their partners.
For the types of H.P.V. that cause genital
cancer, the results were even more striking. About 18 percent of circumcised men were infected at the end of two years, compared with almost 28 percent in the control group. Even after adjustment for types of sexual practices, symptoms of sexually transmitted infections and other variables, the circumcised men had a 35 percent reduced risk of infection.