Atlanta ? Circumcision, which has helped prevent AIDS among heterosexual men in Africa, doesn’t help protect gay men from the virus, according to the largest U.S. study to look at the question.

The research, presented at a conference Tuesday, is expected to influence the government’s first guidance on circumcision.

Circumcision “is not considered beneficial” in stopping the spread of HIV through gay sex, said Dr. Peter Kilmarx, of the U.S. Centers for Disease Control and Prevention.

However, the CDC is still considering recommending it for other groups, including baby boys and high-risk heterosexual men.

UNAIDS and other international health organizations promote circumcision, the cutting away of the foreskin, as an important strategy for reducing the spread of the AIDS virus. There hasn’t been the same kind of push for circumcision in the United States.

For one thing, nearly 80 percent of American men are already circumcised — a much higher proportion than most other countries. Worldwide, the male circumcision rate is estimated at about 30 percent.