10 USC 532 - Qualifications for original appointment as a commissioned officer

(a) Under regulations prescribed by the Secretary of Defense, an original appointment as a commissioned officer (other than as a commissioned warrant officer) in the Regular Army, Regular Navy, Regular Air Force, or Regular Marine Corps may be given only to a person who
(1) is a citizen of the United States;
(2) is able to complete 20 years of active commissioned service before his sixty-second birthday;
(3) is of good moral character;
(4) is physically qualified for active service; and
(5) has such other special qualifications as the Secretary of the military department concerned may prescribe by regulation.
(b) 
(1) Original appointments in the Regular Army in the Medical Corps or Dental Corps, and original appointments in the Regular Air Force with a view to designation of an officer as a medical or dental officer, may be made in the grades of first lieutenant through colonel. Original appointments in the Regular Navy in the Medical Corps or Dental Corps may be made in the grades of lieutenant (junior grade) through captain. Such appointments may be made only from persons who are qualified doctors of medicine, osteopathy, or dentistry.
(2) To be eligible for an original appointment as a medical officer, a doctor of osteopathy must
(A) be a graduate of a college of osteopathy whose graduates are eligible to be licensed to practice medicine or surgery in a majority of the States;
(B) be licensed to practice medicine, surgery, or osteopathy in a State or in the District of Columbia;
(C) under regulations prescribed by the Secretary of Defense, have completed a number of years of osteopathic and preosteopathic education equal to the number of years of medical and premedical education prescribed for persons entering recognized schools of medicine who become doctors of medicine and who would be qualified for an original appointment in the grade for which that person is being considered for appointment; and
(D) have such other qualifications as the Secretary of the military department concerned prescribes after considering the recommendations, if any, of the Surgeon General of the armed force concerned.
(c) Original appointments in the Regular Navy or Regular Marine Corps of officers designated for limited duty shall be made under section 5589 or 5596 of this title.
(d) 
(1) A person receiving an original appointment as a medical or dental officer, as a chaplain, or as an officer designated for limited duty in the Regular Navy or Regular Marine Corps is not subject to clause (2) of subsection (a).
(2) A reserve commissioned officer appointed in a medical skill other than as a medical officer or dental officer (as defined in regulations prescribed by the Secretary of Defense) is not subject to clause (2) of subsection (a).
[(e) Repealed. Pub. L. 108–375, div. A, title V, 501(a)(1), Oct. 28, 2004, 118 Stat. 1872.]
(f) The Secretary of Defense may waive the requirement of paragraph (1) of subsection (a) with respect to a person who has been lawfully admitted to the United States for permanent residence, or for a United States national otherwise eligible for appointment as a cadet or midshipman under section 2107 (a) of this title or as a cadet under section 2107a of this title, when the Secretary determines that the national security so requires, but only for an original appointment in a grade below the grade of major or lieutenant commander.