Q: I am 29 years old and I noticed that my scrotum and testicles are small when I took a shower. When I feel them carefully, it seems that only one side has testicles, and the other side can barely be felt. What is this problem? Will it affect fertility? A: Under normal circumstances, the size of the scrotum can be affected by the external temperature. When the temperature is high, the scrotum becomes larger, and when the temperature is low, the scrotal muscles contract and the scrotum becomes smaller. However, if you find that the scrotum is always smaller than normal, you need to rule out some other diseases. One of the most common is scrotal dysplasia caused by cryptorchidism. Cryptorchidism is a condition in which the testicles unilaterally or bilaterally do not descend to the scrotum after birth and stay anywhere in their normal descent (including the abdominal cavity, inner ring, inguinal and outer ring, etc.), resulting in the absence of testicles in the scrotum or the presence of testicles in only one side. Since the temperature of the abdominal cavity or subcutis is higher than that of the scrotum, the sperm-producing function of the testes that have not descended into the scrotum will be impaired and may become malignant. It is recommended to visit the urology department of local hospital. The best time to treat cryptorchidism is generally considered to be before the age of two. If the testicle still does not descend into the scrotum after the age of one, early surgery is necessary. There are some individual differences in testicular size, and there are not many small testicles that are truly congenital dysplasia. If the secondary sexual characteristics are normal, this possibility can be basically excluded. If one testicle is cryptorchid and the other testicle is normal, fertility is usually not affected.