Doctor of Medicine

A Doctor of Medicine, abbreviated MD, was an Earth title to an accredited medical physician. This title was adopted by the Federation.

In the mystery novel Dangerous Ground, the protagonist, Doctor John Rawley, earned his MD upon graduation from Johns Hopkins in the mid-20th century. 

In Dangerous Ground, Doctor John Rawley was educated in this university before transferring to Johns Hopkins for his MD.

Leonard McCoy became an MD by the time he was assigned to the USS Enterprise (NCC-1701) in 2266. 

Between 2270 and 2273, Christine Chapel became an MD, a fact noted by Leonard McCoy when he returned to the Enterprise during the V'Ger incident. 

In 2365, according to a directory on Starbase 515, several doctors had earned this title and were posted to this base. They were Brian Faul, Sam Freedle, Les Landau, Scott Luhrsen, Robert McCullough, Robert Metoyer, and Adele Simmons.

Medical careers in Starfleet varied depending upon specialties. In order to be a chief medical officer, a physician was required to be highly skilled in both surgery as well as in general medicine.