It's tricky keeping all the family trees straight on Game of Thrones, especially when some are secret, some are generations long, and many involve characters who've never appeared on screen, but only been talked about. That's why many know that Jon and Dany are related, but don't know exactly how. So are Jon Snow and Daenerys brother and sister on Game of Thrones? Though they are the same age, they are not siblings.
There are several plot points in Game of Thrones that are difficult to keep up with. Only dedicated fans get all the details. The most important details, of course, have to do with Jon's mysterious parentage. He grew up thinking he was Ned Stark's son, but as it turned out, that wasn't true at all. In fact, he may not even be a bastard. So how is he related to Daenerys again? Is he even related to Daenerys? The other day my mother insisted to me that Jon's real father was Robert Baratheon. She thought it was obvious. Hey he was also engaged to Lyanna Stark at one point so maybe she's right. However, most people accept that Jon is the son of Rhaegar Targaryen and Lyanna Stark. So let's break it down.
Daenerys's father was Mad King Aerys, the one that enjoyed burning people alive. Aerys, married to his sister Rhaella, had three children, Rhaegar, Viserys, and Daenerys. Rhaegar basically kicked off the rebellion when he won in a tourney and gave his winning roses to Lyanna Stark, Ned Stark's sister, instead of his own wife, Ellia Martell. Then it is said that Rhaegar kidnapped Lyanna and raped her (on a side note, this may not be true at all). Lyanna then (nine months later) gave birth in the Tower of Joy, which Bran saw in his vision, to Jon Snow. Sometime in this same year, as she is fleeing for her life, Rhaella gave birth to Daenerys at Dragonstone.
So while Jon grew up thinking his parents were Ned Stark and some random woman his dad hooked up with during the war, they were actually Rhaegar Targaryen and Lyanna Stark. Rhaegar Targaryen was Daenerys's older brother, even though he died right before she was born. Therefore, because Jon's father was Dany's brother, Jon is Dany's nephew. Hopefully that makes you feel a little less queasy about the incest that's about to go down than it would if they were siblings. Personally, I do feel a little better about it. But just a little. What has this show done to me?