Cryptorchid penis in infants may be associated with congenital dysplasia, overweight, surgery or trauma. 1. Congenital dysplasia: for example, congenital shortage of foreskin and narrowing of the foreskin cavity can lead to cryptorchid penis. 2. Excessive obesity: infants are overweight, resulting in excessive prepubic fat accumulation, so that part of the penis is buried in the fat tissue, which will lead to cryptorchid penis, and when the baby’s weight is reduced, it will be able to recover on its own. 3. Surgery or trauma: Surgery involving the penis or trauma to the penis area may result in scarring of the wound area, which can lead to cryptorchid penis. It is recommended that babies with hidden penis should be examined by a doctor to identify the cause of the condition and to carry out targeted treatment.