We've been waiting all season for it to happen, and Daenerys and Jon Snow finally hooked up in the Season 7 finale of Game Of Thrones. And now that we've all finally had a chance to catch our breath from that momentous scene, we definitely need to talk about what exactly it could mean for the two characters. Specifically, would Jon and Dany's baby be the rightful heir to the Iron Throne? Because damn, there's a lot to think about in regards to that possibility.
This theoretical baby is one that fans have been speculating about in regards to Daenerys' potential fertility for a while now. Though Daenerys believes that she can't have children based upon a comment made by healer-witch Mirri Maz Duur, it seems likely that the statement wasn't exactly trust worthy. After all, as Jon pointed out in the Season 7 finale, the woman who told Daenerys that she was barren did so right after murdering her husband. As far as reliable foreseers go, she probably wasn't the greatest.
Which means that there's still a chance that Daenerys can have children, and that her union with Jon could push that particular plot point to fruition. However, whether or not that child would become the rightful heir to the Iron Throne is a question completely dependent on the extremely complicated nature of the Targaryen family tree.
With the revelation in the Season 7 finale that Jon is actually Aegon Targaryen, and as such is a legitimate heir to the throne, the dynamics between Jon and Daenerys have shifted. Despite the fact that this means that Dany is Jon's aunt, Aegon has a stronger claim to the throne than she does. Daenerys might be the last of House Targaryen, but Jon's Father was her older brother, and thus ahead of her in the family tree which then makes Jon the ultimate heir to the throne.
If Daenerys and Jon were to have a baby together then that child would be next in line for the Iron Throne, meaning that the line of succession would be Jon, followed by their child, which would then leave Daenerys last in line as the rightful heir to the Iron Throne.
Of course, much of this is also dependent on whether Jon's true identity is revealed. But considering that Sam and Bran have rushed to send a raven to him, it seems likely that Season 8 could begin with this revelation, which in turn could have enormous implications on Jon and Daenerys' lives, and relationship. Although, considering that incest is hardly anything new to the Targaryens, it's likely that the two characters being secretly related will be the least upsetting part about it.