There is no medical reason for circumcision, and no major medical association recommends routine circumcision. Circumcision, like any surgery, has risks of adverse medical events including surgical error, severe pain, infection, and prolonged bleeding.
Some boys are circumcised for cultural or religious reasons. For example, circumcision is practiced by Jews and in some sects of Islam. Most other religions including Christianity, Hinduism, and Buddhism do not practice circumcision. While the vast majority of the world's men are uncircumcised, circumcision became a cultural practice in a few countries, for example the United States. Circumcision became popular in the late 19th century as a method to keep young boys from masturbating. Gradually, the practice of routine infant circumcision became widespread in the United States. However, circumcision rates have been declining in the United States for a number of reasons. Among them are that circumcision has no known medical benefit and that circumcision can decrease the sensitivity of the penis during sexual activity. Doctors no longer recommend routine infant circumcision, and as a result the rate of circumcision in the United States is falling. In the 1980s up to 80% of newborn males were circumcised. By 2007, less than 40% of newborn males were circumcised.