The US military has a long tradition of using physician assistants (PAs). The Army began using PAs in 1971 in an effort to supplement the physicians and surgeons in the medical corps. As their numbers grew, PAs gradually replaced general medical officers assigned to battalions. Later, specialty positions developed in aviation medicine, orthopedics, and emergency medicine. The need for a PA serving as an adviser in the major commands slowly developed at all levels of leadership. In 2015, the Army removed limitations on female PAs assigned to combat units. PAs lead in tactical and clinical settings, filling command roles, senior clinical positions, and administrative leadership roles.