Each of the specialties in medicine has established its own curriculum, which defines the length and content of residency training necessary to practice in that specialty. Programs range from 3 years after medical school for internal medicine and pediatrics, to 5 years for general surgery, to 7 years for neurosurgery. Each specialty training program either incorporates an internship year to satisfy the requirements of state licensure, or stipulates that an internship year be completed before starting the program at the second post-graduate year (PGY-2).