Is people growing 3 sets of teeth for real or are you all joking?

People do not naturally grow three sets of teeth. Humans typically develop two sets of teeth: primary (baby) teeth and permanent (adult) teeth. Primary teeth typically begin to erupt around 6 months of age and are usually all present by age 3. Permanent teeth begin to replace primary teeth around age 6 and are usually all present by age 21. In rare cases, some people may develop an extra set of teeth, known as supernumerary teeth. Supernumerary teeth can occur anywhere in the mouth and can vary in size and shape. They are usually removed by a dentist to prevent crowding and other dental problems.