A little boy named Tettchan is embarassed by his funny-looking bellybutton and wonders what function it serves. He discovers that it was once was a cord that connected him to his mother before he was born. This simply written story discusses pregnancy, but not conception. There is a discreet illustration of Tettchan's mother giving birth---her breasts are visible, but not much else---and an explanation of how the umbilical cord was cut. Tettchan's mother then nurses him while his father watches lovingly. The author explains how the cord dries and falls off, and how each person's bellybutton is a memento of his or her birth. A very sweet little book.