A pediatrician is a physician who specializes in the care of children from birth to age 21. They focus on children's physical, emotional, and social health by diagnosing and treating diseases, injuries, and providing preventative care. It takes 12 years of education after high school to become a pediatrician, including 4 years of undergraduate study, 4 years of medical school, 3 years of residency training in pediatrics, and passing the MCAT. Pediatricians earn an average salary of $174,804 annually in the United States.