Patients with cryptorchidism often come to the clinic because of a hollow scrotum and the absence of testicles inside. There are also patients who come to the clinic with the complaint of “hernia”, or who come for examination because of bilateral cryptorchidism and infertility after marriage. Unilateral cryptorchidism is a type of cryptorchidism and includes two types of cases: undescended testicles and ectopic testicles. If one side of the testicle stops on the way of descent and does not enter the scrotum on the same side, it is called undescended testicle or incomplete descent; if the testicle leaves the normal descent pathway and does not enter the scrotum, it is called testicular ectopic, generally the former is more common. Does unilateral cryptorchidism affect fertility? If cryptorchidism is operated in time at an early stage, it will not affect fertility; if cryptorchidism is not treated by surgery at an early stage, it may cause testicular damage such as degeneration of varicocele, atrophy of epithelial cells and spermatogenic dysfunction, which will easily lead to infertility. In addition, if the other testicle is compensatingly enlarged, its fertility is also possible despite the serious damage on the affected side. Although the effect of unilateral cryptorchidism on reproductive function is not as absolute as bilateral cryptorchidism, the chance of causing infertility is still quite high, so treatment should be early and timely, and the treatment of cryptorchidism should be carried out in early childhood to pediatric period. Cryptorchidism is a great danger. Studies have found that the testicles of children with cryptorchidism have obvious pathological changes from the age of 2, and they get worse after the age of 5. Cryptorchidism is in a relatively high temperature environment, which is very unfavorable to testicular development and sperm production after puberty, and can cause significant testicular atrophy and hinder the occurrence of sperm, causing serious harm to patients’ reproductive health, and also has a high chance of cancer and endangering patients’ lives. Regardless of the cause, cryptorchidism can affect the production of sperm due to the high temperature around it, resulting in less sperm or no sperm, thus affecting the fertility of the patient in adulthood. Treatment of cryptorchidism Since bilateral cryptorchidism still has the possibility of natural descent within 12 months, it can wait; those whose testicles still have not descended after 12 months should seek the help of a specialist. Some children can obtain testicular descent after systematic application of endocrine treatment for 1 to 2 months; children with unsatisfactory results of cryptorchidism treatment should undergo bilateral testicular traction fixation within 2 years of age to solve the problem of cryptorchidism through surgery, and as long as the surgery is successful, there is hope of restoring fertility. Unilateral cryptorchidism often has a low efficiency of endocrine treatment, so surgery can be considered directly. after the age of 2, irreversible damage of cryptorchidism starts to occur, so the choice of the time of cryptorchidism surgery is very important. Treatment of cryptorchidism is not only for the consideration of future fertility, but cryptorchidism also has the chance of inguinal hernia, injury, cancer, and torsion, which can have a significant psychological impact on the male spirit. Cryptorchidism is more likely to become cancerous after the age of 20, which is 20 to 48 times more likely than normal testicles. Even if the cryptorchid is “placed” in the scrotum after adulthood, it cannot completely prevent cancer in the future. However, no matter what treatment method is used, it must be done within two years of the child’s age.