Answer:
   
   Although some modern Reform Jews use medical doctors to perform the
   circumcision, this is not the traditional method. Traditionally, the
   male infants are circumcised in the home or the shul on the eighth day
   after birth, surrounded by family and friends, and held by the sandek
   (an adult being honored by the parents, often a grandfather). The
   infant is given a little wine, and the ritual is performed by a
   specially trained Mohel, whose sole function is to perform
   circumcisions.
   
   Traditionally, the father is supposed to perform the Brit. As most
   fathers do not have the appropriate training, a Mohel performs the
   Brit. It is customary, that if possible, a Mohel will perform his
   first Brit on his own son - under the supervision of an experienced
   accredited Mohel (his teacher).
   
   Note that Mohelim are not unique to the more traditional Orthodox
   movement. The Reform and Conservative movements also train and
   accredit Mohelim; often, the Mohel is a practicing M.D. (For example,
   Dr. Samuel Kunin (a Reform Mohel in Los Angeles CA) and Dr. Robert
   Lewis (a Conservative Mohel in Columbus OH) are practicing
   urologists).