Your belly button marks the spot where your umbilical (say: um-BIL-ih-kul) cord was once attached. This cord is a soft, bendable tube that carried nutrients — vitamins and minerals — from your mother to you, back when you were in her belly (womb).
When a baby grows inside its mother, it can't eat food or breathe air. That's where the umbilical cord comes in. Not only does it carry nutrients, but it also takes away the waste that the baby doesn't need anymore.
Bye, Bye, Cord! Hello, Button!
When the baby is born, he or she lets out a cry. This lets everyone know that the baby can breathe on his or her own. The baby will also soon be drinking milk and getting rid of wastes on his or her own — as anybody who has seen a dirty diaper will tell you!
The brand-new baby doesn't need an umbilical cord anymore. The doctor cuts the umbilical cord and a tiny stump is left. When this stump falls off after a few weeks, the baby is left with his or her very own baby belly button.
The belly button might be an innie or an outtie — which kind do you have?