Last night’s Game of Thrones, in which Jon Snow came back to life, was a big night for those of questionable parentage.First, Jon Snow came back to life. Second, Ramsay Bolton stabbed his father and fed his half-brother to the dogs rather than face the possibility of losing his legitimacy. And Tyrion Lannister unleashed some dragons. Jon and Ramsay are more or less the opposite ends of the bastard spectrum; Jon was embraced by his family and became an agent for good, Ramsay's father lorded his parentage over him like an executioner's ax and he became very evil. Tyrion represents kind of a third path for a bastard, wherein his family half-accepted him but eventually drove him out.Wait, you say. What? We know who Tyrion’s mother and father are. But do we really?A popular fan theory (A+J=T, it’s called) suggests that Tyrion’s father was the mad king Aerys Targaryen. That would make him Daenerys’ half-brother and give him a claim to the crown.Like R+L=J , the theory that Jon's father is secretly Rhaegar Targaryen, A+J=T has a lot of evidence on its side. First, there’s Tyrion’s fascination with fire, an element tied to the Targaryens. Recall his defense of King’s Landing at the Battle of Blackwater. Lending more credence to the theory was last night's episode, where we saw his lifelong interest in dragons manifest. Now, that’s not uncommon — dragons own — but he is the only character for whom it’s really emphasized, and who has gotten that close to the beasts without being flame-broiled.Also, there's Tywin’s repeated epithet that Tyrion is “No son of mine.” We ascribed this to Tywin being kind of a big jerk, but maybe he was being literal.Finally, we’ll quote from this fan explanation.“Joanna [Targaryen] was rumored to have had an affair with Aerys and was dismissed from court by Rhaella [his wife] because Aerys was making Joanna a whore (suggesting that an affair occurred between Joanna and Aerys while Aerys and Rhaella were married and might have continued even after Joanna married Tywin).”Finally, his mother died during childbirth. Much like Dany’s mother. And Jon’s. Hmm.