Only a few boys can still grow taller at the age of 20. Normally, males start at the age of 13 to 14 years old and enter into a period of rapid growth, when the body can grow taller rapidly. At the age of 17 to 18 years old, male androgens begin to secrete, the epiphysis begins to slowly close, the rate of height development began to decline. By the age of 20, the male gonads are basically mature, the epiphysis basically closes, and the height is basically finalized. However, a few boys develop later, may be 14, 15 years old only began to develop, his androgens appear later, gonadal maturity is slower, epiphyseal closure time delay, to the age of 20 years old still have the possibility of growing taller. It is suggested that if a 20-year-old boy wants to know whether he can still grow taller, he can go to the hospital to have his bone age determined, take a picture to see whether his epiphyses are closed or not, and have his sex hormones tested.