hahahaha, I've never even heard that one.
There was the time honored "If you keep making that face, it's going to freeze like that."
"Drugs are bad" (Alright, they were a lot of fun for a while, but I'm done with that shit now)
"If you don't stop playing video games your eyes are going to go bad"
Yeah, my parents didn't lie too much that I can remember.
Me on the other hand....
-fuse.
p.s. I'm not implying that I have children.