Although studies show the relative risk of developing a urinary tract infection (UTI) in the first year of life is higher for baby boys who are uncircumcised, the AAP policy concludes that their absolute risk of developing one is low -- approximately 1 percent at most. Research indicates that during the first year of life an uncircumcised male infant has at most about a 1 in 100 chance of developing a UTI, while a circumcised male has about a 1 in 1000 chance.
Studies conclude that the risk of an uncircumcised man developing penile cancer is more than three-fold that of a circumcised man. However, the AAP policy notes that in the United States only nine to ten cases of this rare disease are diagnosed per year per one million men, indicating that while the risk is higher for uncircumcised men, their overall risk is extremely low.
Some research suggests that circumcised men may be at a reduced risk for developing syphilis and HIV infections. However, the AAP policy states that behavioral factors continue to be far more important in determining a person's risk of contracting sexually transmitted diseases than circumcision status.
Considerable new evidence shows that newborns circumcised without analgesia experience pain and stress measured by changes in heart rate, blood pressure, oxygen saturation and cortisol levels. Other studies suggest that the circumcision experience may cause infants to respond more strongly to pain of future immunization than those who are uncircumcised.