Other reasons have been given since then, but all of them, including the claim that circumcision prevents cancer of the penis, cancer of the cervix and venereal diseases, have been disproven. We now know that the foreskin is a normal, sensitive, functional part of the body. Many circumcised men have reported that they have been teased because they didn't have a foreskin. Just being strapped down is frightening for a baby. The often repeated statement that babies can't feel pain is not true.
Babies are as sensitive to pain as anyone else.
Most babies scream frantically when their foreskins are cut off. Some lapse into a coma. The reason some babies don't cry when they are circumcised is that they can't cry because they are in a state of shock. Most babies are circumcised without an anesthesic. Anesthetics injected into the penis don't always work.