As part of training in medical school, most doctors are trained to perform routine circumcision on newborns. It is usually performed within a few days after birth in the hospital. This is circumcision, but only a mohel can perform a bris. He is not only trained extensively in medical techniques but he is an expert in Jewish law and ritual related to this time-honored ritual.
After completing extensive apprenticeship under an experienced mohel, the apprentice performs several circumcisions under the supervision of his mentor. After proving his expertise in all areas related to the bris, he receives his certification.
It is noteworthy to mention that many doctors will call upon a mohel to circumcise their own sons, recognizing their expertise in this area. Even Queen Elizabeth called upon the official mohel of the London Jewish Community when Prince Charles was born.