Growth has been long recognized as a measure of the health of individuals and is an indication that nutrition plus health, genetic potential, and hormonal balance is a basic formula regulating growth and is thus responsible for a child growing at a normal rate. That being said, there is no proven way to predict a child's adult height. However, several methods can provide a reasonable estimation for growth. A popular formula is to add
your height and your son's father's height in either inches or centimeters, add 5 inches and then divide by two. Most likely your son will reach his adult height within 2-3 inches of this estimation. A major growth spurt occurs at the time of puberty, usually between 11 and 15 years in boys, and then slows down considerably. In general, boys end their growth in their late teens but can be longer. It is not surprising, however, that some boys continue growing until they reach 21 years of age. As mentioned, it is because growth depends not only on their parents' genes but also on nutrition and hormonal balance. I hope you find the information helpful. Since you have concerns about your son's growth, I would suggest that you have a consultation with a primary care physician
to have your questions answered in detail.