Orchidism is a congenital disorder in which the gonads develop abnormally, resulting in urinary malformations that cause unilateral or bilateral absence of testicles. Azoospermia is considered to be caused by genetic predisposition, testicular torsion, and embryonic injury. 1. Genetic factors: it may be related to NR5A1 gene mutation, due to the mutation of genetic information leads to atrophy and degeneration of testis, and azoospermia occurs. 2. Testicular torsion: Testicular torsion or spermatic cord vascular embolism during pregnancy or shortly before or after birth, resulting in ischemia of testis due to obstruction of testicular blood supply, which leads to gradual atrophy and degeneration of testis to form anorchidism. 3. Embryonic injury: Infections, toxin exposure, defective immune mechanism, vascular occlusion, trauma, etc. during fetal period can cause gonadal development to be hindered, resulting in atrophy or disappearance of testicles, and thus the development of azoospermia. As anorchidism is a congenital disease, and in some cases, it can be combined with absence of vas deferens, it is recommended that patients with this symptom should go to the hospital for checkups, and then choose the appropriate treatment plan under the guidance of the doctor.