Most adult starfish of other species do reproduce via a separate male and female. Females usually produce eggs that males fertilize in the seawater. At that point, the fertilized eggs develop and grow before becoming little starfish that will attach themselves to the substrate and start the whole process over again.
The extreme self-parenting starfish often have no such male-female interaction.
As a hermaphrodite, the individual produces its own eggs, which are then fertilized right inside the body, likely with that same individual's own sperm.
"The fertilized eggs are not sent out into the environment for development, and instead the parent keeps the developing embryos inside its body, where they complete their embryonic development and become juvenile sea stars (starfish)," Hart explained.
He added, "In some species, these juvenile sea stars eat each other, and grow to become relatively very large."
A family with little or no sex and with kids that eat each other predictably has problems.