Anyone who really knows won't say. Anyone who says, doesn't really know.
Well, according to the famous song by the Archies, "Baby" is the same person as "Sugar Sugar," and also "Candy Girl". This obviously proves that the little girl this season is the daughter of Kandyman (you know, the killer robot made of candy from "The Happiness Patrol"). Moffat said that Kandyman would be the main villain in series 5, and get married, but that was obviously just to throw us off the trail of his real plan. And, if you're still reading this and taking it seriously, please contact me about purchasing a bridge.
In Brooklyn, is it?