Because you need a soul for that.
Vader: Luke: Vader: I need a kidney.
You need a knife to get in the box.
The baby has a soul.
Adam Levine: I sold my soul to the devil. Interviewer: Excuse me Adam Levine: Practice.
He whipped out his wand and yelled, "***Shtupify***!".
One had a horcrux, the other had a whorecrush..