All medical practitioners undergo training initially at medical school to become medical doctors.
They then undergo a period of training in one or more teaching hospitals as a 'resident', during which they are assigned to work on various wards of the hospital. After that period of residency they can apply for a licence as a general medical practitioner or can continue training in a specific area of specialty, such as pediatrics. Being licensed as a doctor and being recognized as a specialist are separate issues altogether. Recognition as a specialist in this country is the purview of the Royal College of Physicians and Surgeons of Canada. As the specialty of pediatrics has expanded, so have the number and types of subspecialties, or more specialized areas of medical work.