Final answer:
Stewart's parents are concerned about his growth due to his shorter height and lower muscle strength and mass. Although his body and limb proportions are normal, he has an increased distribution of fat throughout his body. Stewart's growth has been slow, with less than 2 inches of growth per year.
Step-by-step explanation:
Stewart's parents are concerned about his growth, as he is shorter than his classmates and appears to have lower muscle strength and mass. Stewart's height is approximately 22% shorter than the average male height at his age. However, his body and limb proportions are normal, and he has an increased distribution of fat throughout his body. Stewart's growth has been slow, with less than two inches of growth each year and some years showing almost no growth.