Why do some guys think telling girls they look like the mother of their child is a good pick-up line?

I think in guys’ minds they see it as a compliment but I just find it weird. especially when you two barely know each other or just started dating. And assuming the girl wants to be a mother. Had a guy from school tell me this and tried touching my stomach and i got freaked out very fast. I’m trying to see how we’re supposed to react to this comment.