Answer. The factors that determine how to grow size during adolescent years include;The DNA of a human being has 700 different genes to determine the height of an individual.The hormone of the pituitary, the thyroid hormone, and the sex hormones are required for growth. They determine the growth of a girl or a boy. Among the sex hormones, testosterone and estrogen are essential.The sex of a child plays a role in the growth of the body. Usually, boys grow more. This occurs for a longer period than that in girls.Regular exercise and a proper diet can also act as a catalyst for growth. Exercise helps in physical development by sharpening the body and making the body stronger.