Newborns whose balls did not descend belong to cryptorchidism, the etiology of which is still unclear, and may be caused by genetic factors, abnormal testicular development, anatomical and structural abnormalities, and endocrine factors. 1. Genetic factors: the incidence rate of those with a family history of cryptorchidism is higher than that of normal people, which may be related to genetic factors. 2. Abnormal testicular development: the normal descent of testis can be affected by its own developmental defects, resulting in the fusion of both testes, oversized testes, or testes failing to respond to the corresponding hormones, and so on. 3. Anatomical structure abnormality: such as the blood vessels of spermatic cord are too short, the fascia covers the entrance of scrotum, etc., which can affect the descent of testis and trigger cryptorchidism. 4. Endocrine factors: If the endocrine dysfunction of the child affects the testosterone level, it may also trigger cryptorchidism. When the newborn’s balls don’t descend, he should seek medical treatment in time and under doctor’s guidance, so as to avoid the condition from continuing to develop, which will have an impact on the child’s health.