The small external genitalia need to be examined to determine how to increase, as follows: 1, if the boy in adolescence appear low testosterone levels, can cause the external genitalia do not develop the situation, the need for testosterone level detection, after the diagnosis need to intramuscular injection of human chorionic gonadotropin 1500mIU/mL, every other day intramuscular injection, times, continuous use of 10 days, observe the testosterone level and external genitalia If there is a deformity of the urethra, such as the presence of an invisible penis, hypospadias or prepuce, surgery is needed, and patients with prepuce need to be temporarily circumcised to observe the effect, if there is an invisible penis, it is recommended to perform penile reoperation, also known as penile enlargement surgery, which can make the appearance of external genitalia become larger or longer. or longer.