*smiles slightly* I think if Arthur were going to get pregnant, it would have happened by now. He's certainly had ample opportunity.

And they could have been Jack's, remember? It's the same life-overflow with him. Or both.

And, well, I know that they'd be happy to accept me as another parent, but I'm not really part of your family; I can't be, not the way I'd want to, Arthur wouldn't -

And anyway, between you and Teresa I'd just be extra. It'd just be Auntie Lynda again; babysitting and caretaking, helping out with them like I've done all along, and with the Doctor, Rose and Reinette's babies, ever since I first came here.

It's not the same as properly bearing and raising one of your own. Not at all.