You proberly have the UK-version where the kids from the game was removed due to some legislation from some european countries (UK + Germany IIRC). If this is the case you have 2 choices.
either don't finish this quest and some others involving children.
or go to:
http://www.nma-fallout.com/binaries/
and get the children patch (IIRC you also need the US-patch after this, but I can't rememeber excatly anymore) and use this.
I've used it and experience no problems with it, but I think you'd need to restart your game after updating.
[ 09-14-2001: Message edited by: Xandax ]