Cost-benefit analysis is a weighing-scale approach to making business decisions: all the pluses (the benefits) are put on one side of the balance and all the minuses (the costs) are put on the other. Whichever weighs the heavier wins.
However, since the story constantly points out Jon's conflict with his illegitimacy and Ned's strict code of honor, many fans have come up with a theory that actually explains who they think Jon's parents really are. Fans know the theory as R+L=J.. R+L=J would refer to Jon Snow (J) being the child of Rhaegar Targaryen (R) and Ned Stark's sister, Lyanna Stark (L) rather than Jon being the illegitimate child of Ned.
Benjen Stark is the younger brother of Ned Stark and serves as First Ranger in the Night's Watch. He appears briefly at the start of A Game of Thrones first in Winterfell and then later at Castle Black on the Wall where he travels with his bastard nephew Jon Snow.