If I somehow failed my child and he grew up to be a thug murderous gang banger, I'd turn that fuckin lowlife in myself.
If I somehow failed my child and he grew up to be a woman beater and killed a woman for anything other than self defense, I'd turn that fucker in myself. Same for if he raped someone.
If I somehow failed my child and he grew up to be a mentally fucked twat that somehow hurt children, I'd turn that bastard in myself, perhaps after beating the shit out of him.
That's about all though, nothing else comes to mind that would make me insta-call the cops. This is definitely a slippery slope though.