Virgin birth of Jesus
People argue about what Paul meant when he said Jesus was "descended from David according to the flesh."  David, Jeconiah, and Joseph were all in the same family line.  For Jesus to be part of David's family line, he would have to be related to Joseph.  This would mean Joseph had to be Jesus' human father.  However, some people think Paul did not mean Jesus was physically descended from Joseph, only that Joseph acted like Jesus' father.