Worms have both male and female organs. To reproduce, worms need a partner and can't do it alone.  The worms reproduce through a process called "oviposition." When the mate arrives, the worm slides back into its saddle, depositing a single egg inside. The male worm deposits sperm in the pore that serves as a receptacle. The worm's clitellum will seal at the ends, creating a cocoon. Within three weeks, the eggs hatch and begin a new life.