Children

Characters who are children, or were children when they were introduced in their respective stories, even if they went on to age into adulthood.

A child is a person under the legal age of majority. Someone under this age is also called a "minor." The concept varies by differences in law and culture. In the United States today, the legal age of majority is 18. In Japan today, the legal age of majority is 20.

Many incarnations of Leonardo, Donatello, Raphael and Michelangelo are children—teenagers, specifically.