Pediatrics is a branch of internal medicine that focuses on children's health. A pediatrician is a primary care doctor for children that oversees a child's mental, behavioral, and physical well-being from birth until the age of 18.
All board-certified pediatricians have specialized education in children's health, in addition to their medical school training. There are also pediatricians with healthcare subspecialties - like pediatric cardiologists, pediatric dermatologists, and pediatric neurologists. These doctors are qualified to diagnose and treat acute and chronic diseases, and can often offer preventative care.