The earthworm's reproductive system is located in the clitellum, a whitish band near the head of the earthworm between segments seven and 15. The exact placement of the organs varies with the variety of earthworm.
Each earthworm has both female and male reproductive organs in the same area of the body. When reproduction occurs, the worms lie side by side and exchange sperm through openings in the clitellum. Next each worm forms an eggs sac, also called a cocoon, with one or more eggs inside. The worms wiggle out of the egg sac dropping sperm inside with their movements, and the sperm fertilizes the eggs. If the conditions are right, the eggs hatch in a few weeks, and one to five baby earthworms emerge from the cocoon.