After going through the intestine, indigestible material goes through the rectal ceca and out the anus. Most sea stars have separate sexes and spawn their gametes into the water for fertilization. External fertilization must occur in the right light and temperature to be successful. To ensure this success, a sea star will release pheromones with its sperm or eggs to lure others to the area to spawn. A sea star can also reproduce asexually by dividing the central disc in two and regenerating each half.
Embryos feed on plankton and are ciliated.
After gastrulation, the embryo becomes a larva, which forms arms and grows into a juvenile sea star. The juvenile eventually matures into an adult. Many sea stars can regenerate body parts. If a detached portion of a sea star contains part of the central disc, that portion can grow into a brand new star. Regeneration usually takes up to one year to complete.