The branch of medicine is concerned with the development, care, and diseases of babies and children. A pediatrician is a medical doctor who manages the physical, behavioral, and mental care for children from birth until age 18. A pediatrician is trained to diagnose and treat a broad range of childhood illnesses, from minor health problems to serious diseases. Pediatricians have graduated from medical school and completed a 3-year residency program in pediatrics. A board-certified pediatrician has passed rigorous exams given by the American Board of Pediatrics. To remain certified, pediatricians have to meet regular continuing education requirements.