The Series Better End With Being A Father And Raising His Kids - Tumblr Posts
Jon the future Father
An early hint that it's Jon and not Robb who is destined to carry on the line of House Stark is how GRRM chooses to portray them with children, especially their younger siblings.
It's Jon who advises Bran, gently guides Rickon, comforts and encourages Arya, who is shown jubilant when Bran wakes, who worries about his sisters. It's Jon who gave Bran a fish to take home, Jon who tells Tyrion to comfort Rickon with the promise of "all my things".
GRRM could have given Robb similar scenes to interlink with the way his younger siblings idealize him in his absence. But we get no such thing. He is overwhelmed with Rickon's distress, receives comfort from Bran rather than giving it, leaves Bran behind in the woods, is given zero interaction with his sisters and only mentions them to complain about Sansa's lettter, compassionlessly unable to comprehend her obvious situation. He'll go on to refuse to trade for them, remains focused on his role as Ned's avenging son, rather than as protector of his living family.
While Robb needs an "heir", it is Jon who is described to have dreamed of "children". It's not Robb who mirrors Jon in what he would name his sons, that was only ever Jeyne, the only one whose grief is shown over the lost opportunity. "He liked that, I think." She isn't even sure.
Robb is a warrior king, but GRRM utterly avoids showing him in a position that could be interpreted as fatherly. And he never gets to live long enough to become a father to the next generation of Starks. GRRM makes sure to emphasize that his enemies prevented it from ever happening. He remains the Young Wolf forever.
Jon, meanwhile, is shown in a paternal caring light in his very first appearance.
Jon likes children. He is good with children. He wants children. This matters because of the massive role parenting styles play in the books. Tywin's children are monsters because he made them that way. Ned's children are resilient because he and Catelyn raised them responsibly, lovingly, in spite of some failings.
Jon being emphasized to have the skillset to raise children well is a very important signal that he is fit to have a hand in the next generation of House Stark, that his presence and influence will be not just possible but vital. It's not his "blood and seed" that is required, it is his whole person.