User blog comment:Kranes/Question of the week:/@comment-939754-20100626203425

I assume the process is much more gradual. When the Little Sister hits puberty, they start their violence. Splicers can report the behavior, and soon they'd send a group of Splicers to split them up. Newer Big Daddies would be trains to give up violent Little Sisters, and older ones would simple be overwhelmed to give away the Little Sister. They'd then begin the process of amending to the Little Sister's conditioning to function as a Big Sister, armoring them and such.