When a woman is impregnated from anal sex.
Not only is the child a mistake, but its a dirty mistake.
Bob you are totally a turd baby.
A baby born out of anal sex. This is where lawyers come from.
Bob1: I was at the law school yesterday watching the new lawyers graduate. What a bunch of jerks.
Bob2: Their mothers are all anal sex addicts. That's how you get a Turd Baby.