First of all, let’s understand what is cryptorchidism and the difference between cryptorchidism, sliding testis and retracted testis. Cryptorchidism: Cryptorchidism in children is the absence of testicles in the scrotum, including testicular agenesis, ectopic testicles, undescended testicles and incomplete testicular descent, which means that the testicles do not follow the normal development process and fail to descend into the scrotum. The testicle on the side of the baby that does not reach the scrotum in cryptorchidism usually has varying degrees of dysplasia. Sliding testis: If the testis can be felt in the groin area, and the testis can be gradually pulled down to the scrotum, to the point where it quickly retracts back to the groin area after being released, it is called a sliding testis, and the sliding testis needs to be treated surgically. The sliding testicle is also a kind of cryptorchid from the big concept. Retracted testicle: The testicle hides in the inguinal region, and the testicle is gradually pulled down to the scrotum, to the point that after releasing the hand, the testicle stays in the scrotum, which is called retracted testicle. It usually does not require surgery and is followed up with a pediatric surgeon. When the baby is colder, stimulated by cold, or when the baby is nervous, the levator muscle contracts and the testicle shrinks to the top of the scrotum and cannot be felt in the scrotum, these conditions are called retractile testis. In the case of cryptorchidism, the testicles can be clearly felt in the scrotum when the baby takes a hot bath. What are the dangers of cryptorchidism? How to treat it? Do I need surgery to treat it? Since the temperature and physiological environment in the scrotum is different from that in the groin and abdominal cavity (the temperature in the scrotum is lower), the testicular development of children with cryptorchidism is further restricted, which may eventually lead to non-functional testicles, and testicular torsion and necrosis are more likely to occur, and even testicular cancer may occur over time (as confirmed by medical research)! Cryptorchidism is an important risk factor for male infertility (not having children) and testicular cancer. Therefore, cryptorchidism needs to be treated with surgery as soon as possible. What is the best age for surgery for cryptorchidism? Is the younger the better? Studies have shown that babies are younger before 6 months of age, so observation is recommended and surgery is not done for now. The best age for cryptorchidism surgery is from 6 months to 1.5 years old, preferably not more than 1.5 years old. Babies over 6 months old should be treated by surgery as soon as possible.