Physicians are subject to a number of unique provisions relating to their eligibility for visa issuance.  Also because of the nature of U.S. licensing for medical doctors, physicians often obtain either J-1 visas or H-1B visas for substantial periods of time before they can actually practice medicine in the U.S.  This in itself may impose special burdens on the physicians' desire to be in the U.S. beyond training the physicians' needs.