Cervical cancer is caused by the same virus responsible for genital warts.

The study in Thursday's New England Journal of Medicine found that men with intact foreskins were three times more likely than circumcised men to be infected with the human papillomavirus. That, in turn, may increase the risk of passing the virus on to their sex partners.

The theory is that the skin in the inner lining of the foreskin is especially vulnerable to the virus.

"It will certainly fuel the ongoing debate about the merits of circumcision," said Dr. Michael Thun, an American Cancer Society epidemiologist not involved in the study. He said it raises the question of whether circumcision can reduce the spread of AIDS too.

Studies dating back to at least 1988 have suggested that circumcision offers some protection against AIDS, but the research does not prove it and more definitive studies are under way.

The cervical cancer study, conducted by researchers in Spain and four other countries, looked at nearly 3,800 women, half of whom had cervical cancer, half of whom were cancer-free.

There was only a slight overall difference between the two groups in how many had circumcised partners and how many had uncircumcised ones.

But the researchers found a strong difference in the risk of cervical cancer when it came to women whose partners were especially active sexually. Women whose high-risk partners were not circumcised were five times more likely to get cancer than those whose partners were circumcised.

High-risk men were defined as those who had at least six sex partners and started having sex before 17.

One of the researchers, Dr. Xavier Castellsague of the Catalan Institute for Oncology in Barcelona, Spain, said it would not make sense to promote circumcision as a way to control cervical cancer in the United States, where Pap smears usually detect it at a treatable stage.

However, he said circumcision could make a big difference in developing countries where there is no regular screening for cervical cancer.

"If it is shown in trials to be effective, it could be a relatively simple and safe procedure to prevent these life-threatening infections," he said.

Ronald Goldman, executive director of the Circumcision Resource Center, an anti-circumcision group, said the study, supported by the International Agency for Research on Cancer in France, is unreliable because it pools data from seven studies in five countries.

He added: "Cutting off a normal healthy functioning body part to prevent an unlikely disease or infection would be like pulling healthy teeth to prevent tooth decay."

Dr. Stephen Moses of the medical microbiology department at the University of Manitoba said he and other researchers have begun recruiting patients in AIDS-ravaged Kenya for a two-year study of whether circumcision can reduce the spread of the virus.