A pediatrician is a doctor who specializes in the regular care of children, as well as the diagnosis and treatment of illness in children. Young patients are often more complicated to treat because they are still growing and developing.
While pediatricians may sub-specialize in specific therapy areas like oncology, surgery, ophthalmology, and anesthesiology, in general, pediatricians provide services like vaccinations, health exams, and treatment of common ailments and injuries. In addition, pediatricians are trained to handle the complex emotional and behavioral issues faced by children, especially during puberty.
Pediatricians normally see their patients from birth until the age of 18, although some may agree to treat patients into their early 20s, if requested.

A physiatrist is a doctor who specializes in the rehabilitation and physiological treatment of patients with an illness or injury that affects movement.
These specialists have extensive knowledge of the nerves, muscles, bone, and brain. Physiatrists are also experts in pain medication.
Some common conditions that physiatrists treat are rheumatoid arthritis, neurological and spinal disorders and injuries, chronic pain disorders, like fibromyalgia, and musculoskeletal issues, like broken bones and torn muscles.
These physicians also often coordinate a team of other specialists in order to maximize the patient's recovery, such as occupational therapists, speech therapists, neurologists, orthopedists, and counselors.

A family practitioner is a doctor who specializes in caring for people of all ages, at all stages of life. Rather than focusing on the treatment of one disease or patient population, family practitioners are often the doctors that people see for their everyday ailments, like cold and flu or respiratory infections, and health screenings. When necessary, family practitioners will provide referrals for conditions that require the expertise of another specialist.
The doctors may also provide physicals, inoculations, prenatal care, treat chronic diseases, like diabetes and asthma, and provide advice on disease prevention.