Okay, I would answer that for you; but, it would be kind spoilery -- so, do you want to know what the "speculation" is on that one?
I’ve heard the speculation that Jon is actually Ned’s nephew through his sister and the son of the dead prince. Another option is that he’s a bastard by Willa, a nurse.
If John is Lyanna’s son by Rhaegar, it creates a whole potential dynamic of the lost heir to the throne returning to it after the slaughter of the Starks by the Lannisters’.
Theoretical plot resolution, though unlikely on all fronts, Jon Snow marries Daenerys Targaryen, as two Targareyns, as well as an affront to all the noble houses that are feuding.