Occasionally, a person who already holds an M.D. may choose to pursue a second medical degree. This is usually done in order to gain more specialized training in a specific area of medicine. For example, an M.D. who wants to become a surgeon might choose to complete a residency program in surgery, which can lead to a second M.D. degree in surgery.
In addition to the M.D. degree, there are a number of other medical degrees that are available, such as the Doctor of Osteopathic Medicine (D.O.) degree and the Doctor of Dental Medicine (D.M.D.) degree. These degrees allow graduates to practice osteopathic medicine and dentistry, respectively.