I am calling BS on stuttering preventing you from becoming a "great" doctor. i am not in the medical field but the only road blocks i can see is 1) difficulty networking with other doctors, 2) difficulty telling patients information, and 3) difficulty communicating with other medical people in an emergency. 1 is BS because it is a matter of confidence and you have tons of practice in it already, 2 is BS because (at least for me) stuttering almost disappears when you are in a position of authority and/or in a routine situation. 3 is BS because (again, at least for me) the stutter disappears in emergency situations.