I watched this.
I wonder if both of these flatworms ever end up pregnant.
Earthworms are simultaneous hermaphrodites, meaning worms have both male and female reproductive organs, just like flatworms. During sexual intercourse among earthworms, both sets of sex organs are used by both worms. If all goes well, the eggs of both of the mates become fertilized. Can this occur in flatworms? Or in flatworms, one must be the mother and the other the father?