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.
If you've got this far and haven't realized this article will contain Game of Thrones spoilers, this is your final warning. HBO has confirmed, either accidentally or otherwise, who Jon Snow's father is. The finale of Season 6, Winds of Winter, revealed his mother is actually Lyanna Stark, but an infographic on the Making Game of Thrones blog has more information for us. Game of Thrones - The Winds of Winter - Dragons on the Wall.