At birth the foreskin is fully attached to the penis. It gradually begins to loosen, and by age one the glans at tip of the penis itself should be visible. Most boys' foreskin is fully retractable by age four or five, although for a significant percentage this doesn't occur until much later. At that point the foreskin can be folded back over the penis so that it is fully exposed for proper cleaning. The foreskin must never be left folded. That is dangerous and requires an immediate doctor's visit if the penis swells to the point that the foreskin cannot be readily unfolded. Often cold compresses and medications to reduce the swelling are sufficient to return it to normal, but sometimes minor surgery is required to relieve the constriction.

Because uncircumcised penises require special care, parents commonly opt to have the foreskin surgically removed. Although this custom is on the wane, many people still claim there are only benefits to circumcising a child. In fact, a circumcised penis is easier to clean, which reduces the risk of infection. However, infants do feel the pain from the surgery. Moreover, the widespread belief that circumcision does not impact adult sexual functioning is false. The exposed tip loses a good deal of sensitivity.