I have actually never thought about this before! But I think that they would have wanted a big family. Especially Molly, as others have said, she just has so much love to give, and so much protection and everything. But I also think that they wanted a girl. I mean, after having that many boys, and no more after Ginny, it's easy to conclude. But who knows... They are magnificent parents though, so little money they had but their home was so 'Homey' and warm.