ABCNews -- Beyond navigating typical sibling rivalry that exists in any family, some parents with adopted and biological children must also consider the challenges that come with so-called blended families. Much of the tension, however, results not from the children's behavior but that of their parents, several adoption experts told ABCNEWS.com. "If you have parents who say, 'Look, this is how our family came to be,' the kids will accept it," said Allan Josephson, professor of child and adolescent psychiatry at the University of Louisville School of Medicine. "Parents really set the tone [for the kids]." Actress Angelina Jolie is perhaps one of the most notably recent figureheads of a blended family. Having first adopted son Maddox from Cambodia in...