这是什么？
Undescended testes is when a testicle hasn't moved into the bag of skin below the penis (the scrotum) before birth. This can happen on one or both sides. In most cases it does not need treatment. The testicle will usually move down during the first 6 months of life.
If the testicle hasn't moved by 6 months, it's very unlikely to so may need treatment. This is because undescended testes can raise the risk of infertility, testicular cancer, and injury later in life.
In most boys, the testicles will move in and out of the scrotum at different times. When the testicle remains in and can't be moved, it is known as retractile testicles. This is not a cause for concern as the testicle will often settle permanently in the scrotum as they grow.