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.

An otolaryngologist is more commonly referred to as an ENT, someone that can treat medical issues you may be having with you ears, nose, or throat. This is a physician who is specially trained to diagnose and treat conditions of the ear, nose, sinuses, larynx (voice box), mouth, throat, head, and neck. These doctors treat patients through both medical and surgical means. For instance, an otolaryngologist may treat an obstruction of the nasal passage, caused by malformation of the nose, through rhinoplasty.

An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.
These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.
In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.

An oral & maxillofacial surgeon is a physician who surgically corrects conditions of the mouth and surrounding facial structures including the head, neck and jaws. These doctors usually start out as dentists before undertaking extensive surgical and medical training.

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.

An obstetrician & gynecologist, or OB/GYN, is a physician who cares for women throughout their pregnancies, straight through to the delivery of their baby (obstetrician). They also specialize in annual care, as well as the diagnosis and treatment of disorders of the female reproductive system (gynecologist). Many physicians specialize in both of these fields in order to provide complete overall health services to women at every stage of life.