naaah, it's the hand - genetic manipulation stuff, methinks. Dd1 thinks that she might actually be searching for him perhaps, and the getting-dragged-away bit at the end might be her somehow using the hand to call him or something.
Dd1 also pointed out that the Doctor has made it quite plain in the new series that he is a father - he told Rose that he was a dad once, and there have been other times.
You'll find plenty of geeks trying to insist that Susan wasn't really his grand-daughter, though. I'm not one of them, but I do think that this won't be anything to do with her. I'd like it to be, but I think we were fanwanked to death with everything in this weeks episode, I can't see them giving us much more, although it's possible.
I think Rose was actually pregnant with the Doctors child and has somehow sent their child through the void and she is going to kick his arse and then the Doctor will be having sex with someone.
Oh, sorry, no I don't, that's just bound to a be fanfic at some point.