An estimated 10 to 30 percent of babies are born with an outie belly button, or umbilical hernia, which develops in utero when a small part of the intestine pokes through the umbilical ring, preventing the abdominal muscles from meeting. (Heredity and how the cord is cut have nothing to do with the condition.) As the muscles continue to grow during infancy, most outies will disappear by themselves in 12 to 18 months. If the hernia grows larger than one-half inch in diameter after the baby leaves the hospital, or it becomes red or inflamed, consult your pediatrician. In rare cases, these are signs that a piece of bowel is lodged in the hole, which will require surgery.