[MAIN SPOILERS]Cersei and Jaime

I know this is limited to the books, but in ADoD, on the day of the arena fight where Drogon arrives, Daenerys is talking to Ser Barristan on the way to the arena. He mentions that Aerys Targaryen lusted after Joanna Lannister(Tywin’s wife) and took “liberties” during the bedding. Now I don’t know what “liberties” means exactly, but it could mean that Aerys impregnated Joanna Lannister somehow. Logically, since Cersei and Jaime were the first children of Joanna Lannister, it is entirely bloody possible both are bastard children of Aerys Targaryen. Which would be enormously ironic, as then the only “true” son of Tywin Lannister is the stunted, drunken dwarf that his wife died giving birth to. We could very easily have three Targaryen bastards in this book. It is entirely possible that John Snow and Jaime Lannister will be the other “two heads” of the dragon, as Cersei will probably be her “real” father’s daughter and become the Mad Queen.