US researchers found that male circumcision cut the risk of genital herpes and human papillomavirus (HPV) infection, but not the syphilis. The data from two clinical trials in Rakai showed male circumcision reduced also the incidence of HIV infection. HPV can cause cancer and genital warts.
“This new research confirms the substantial health benefits of male circumcision, including reduced acquisition of HIV, genital herpes, HPV and genital ulcer disease”, according to the researchers too.
Another reason for the odd result with syphilis could be the low statistical power of the analysis (presumably because of low numbers of syphilis cases) said the researchers, making it difficult to draw a firm conclusion about syphilis and circumcision.