
Genna Lannister in A Feast for Crows told Jaime that Tyrion was Tywin’s true son, which upset him at the time. It may have even been an open secret among the nobles of Tywin’s generation. When you think about it, the twins' incest and Cersei’s madness may be frowned upon by the rest of Westeros, but they're actually hallmarks of the Targaryen family - as is Cersei's obsession with wildfire and their golden hair. He transmutes the grief into a hatred of Tyrion and his dwarfism. Then, when he finally does have a true-born heir, his wife - who he loved dearly by all accounts in the books - dies while giving birth. Tywin sees his wife assaulted and subsequently impregnated with their firstborn children, whom he has to publicly claim as his own or risk the wrath of the king. We’ve assumed Tywin hated Tyrion because he wasn’t his own son, but it could just have easily been because he was.

But what if the pregnancy that resulted didn’t produce Tyrion, but rather Cersei and Jaime? There’s evidence that Aerys was obsessed with Joanna, Tywin’s wife, and may have raped her. It has also pointed obliquely to Tyrion - since there’s speculation that Tyrion isn’t Tywin’s son, but instead the child of the Mad King Aerys Targaryen. Key to this theory is the idea that "the prince who was promised" is widely assumed to be of the Targaryen bloodline, which has led fans directly to Dany and Jon. Family matters Credit: Mashable composite/hbo All in the family
