Circumcision is often touted for its potential health benefits: reduced risk of urinary tract infections for baby boys, and lower rates of HIV in teens and men. Now a new study shows that it may also cut a man's chances of contracting two more common, incurable sexually transmitted diseases.

Two randomized, controlled trials in Uganda involving 5,534 men found that those who underwent circumcision as adults were 25 percent less likely to become infected with herpes and more than 30 percent less likely to catch human papillomavirus (HPV) than their uncircumcised peers. (Eight percent of circumcised men and 10 percent of uncircumcised men in the study caught herpes; 18 percent of circumcised men and 28 percent  of uncircumcised men contracted HPV.) The research published today in the New England Journal of Medicine didn't, however, find that getting circumcised reduced the risk of contracting syphilis. Previous research has shown that circumcision reduces a man's risk of acquiring HIV by as much as 60 percent.

"The data are very clear that not only does circumcision help prevent HIV, but also has a significant, positive impact on prevention of herpes and HPV," says Anthony Fauci, director of the National Institute of Allergy and Infectious Disease (NIAID), which helped fund the research. He added that reducing men's risk of herpes and HPV would likely cut rates of the infections in women.

Circumcision, the removal of a male's foreskin, may lower the risk a man will catch the infections, Fauci tells, because its moist environment provides the "perfect breeding ground for viruses and bacteria." It can tear and develop sores easily, and if it becomes inflamed, he said, "it gives you much more fertile ground for HIV to be transmitted."

Judith Wasserheit, vice chair and professor of global health at the University of Washington in Seattle who co-wrote an editorial accompanying the study, called the findings a "game-changer" that should make frank discussions with parents about the health benefits of circumcision part of routine medical practice. Rates of newborn circumcision in the U.S. have declined over the past three decades: about 56 percent of baby boys were circumcised in 2006, down from about 65 percent in 1979, according to the 2006 National Hospital Discharge Survey.

There are 50 percent fewer newborn circumcisions in hospitals in the 16 states where Medicaid doesn't cover the procedure than there are in the covered states, research published in November in the American Journal of Public Health shows. Despite growing evidence of its benefits, the American Academy of Pediatrics doesn’t endorse routine infant circumcision, though it's currently reviewing its position. As a result, Wasserheit tells,  "depending on which pediatrician or OB or midwife, either nothing may be mentioned unless the parent asks or the option of circumcision is not presented in terms of potential benefits in protecting the son from these three common, currently incurable sexually transmitted infections."

About 17 percent of people in the U.S. are infected with herpes, at least half will experience HPV at some point and an estimated 3,800 U.S. women died last year of cervical cancer, which is linked to HPV.

"The major message here is that this is really terrific news that ought to shift the way we think about the potential role of male circumcision," Wasserheit says, "from prevention of HIV to this being a great opportunity to protect boys and men from these three currently incurable, viral STIs that are so common."

Transmission electron micrograph showing herpes/Fred Murphy and Sylvia Whitfield, CDC via Public Health Image Library