(WebMD) Circumcision may protect against infection with the virus that causes AIDS.

In a study of more than 3,000 young men, those who were circumcised were 65 percent less likely to be infected with HIV compared with those who were not circumcised.

"Circumcision prevented 6 to 7 out of 10 potential HIV infections," says researcher Bertran Auvert, MD, MPH, professor of public health at the University of Versailles-Saint Quentin in France.

Circumcision was so effective at preventing HIV transmission that the trial was stopped early so that all the young men in the study could be offered the procedure, he tells WebMD.

The study included 3,128 uncircumcised young men aged 18 to 24 in a rural area outside of Johannesburg, South Africa. The men were randomly assigned either to undergo the procedure or remain uncircumcised. All the men were heterosexual.

By about 1½ years later, 51 men who had not been circumcised had been infected with HIV, compared with only 18 who had the procedure, the study showed.

The findings were presented at a meeting of the International AIDS Society.


Too Soon To Recommend Widespread Circumcision

Doctors have long noticed that circumcised men appeared to be at lower risk of HIV infection. But this is the first time that the observation has been confirmed in a well-designed study in which half the men got the procedure and the other half didn't, according to researchers at the meeting.