From what I understand, joseph is not the father of Jesus, so why would his blood line matter? And I am pretty sure the bible lists both Mary and Joe's bloodline. Do I need to look it up for you?<quoted text>
It does for Joseph. Are you asking why not for Mary?
But really, why would a kings bloodline matter period? It all reeks of monarchy. Thus logic shows the story is but an ancient superstitious tale.