Male 23 years old with normal thyroid, normal chromosomes, normal pituitary gland, small testicular hypoplasia may be caused by Kalman’s syndrome, varicocele and other factors, such as Kalman’s syndrome requires androgen therapy. 1. Kalman syndrome: it is a kind of hypogonadotropic hypogonadotropic syndrome accompanied by absence or decrease of sense of smell, which may appear in men with small testicles. Androgen therapy can be given to promote the development of secondary sexual characteristics, and gonadotropins can also be used to help restore the fertility of patients. 2. Varicocele: When varicocele induces testicular atrophy, surgical treatment should be considered, such as high spermatic vein ligation. Patients are advised to clarify the cause and treatment under the guidance of doctors.