"The relationship between the kids all stems from the parent — if the parent has been evenhanded with the children, the kids will accept their situation," Josephson said.
Josephson said that while society's stigma about adoption may lead some to believe that blended families experience the most problems among siblings, he suspects that the familial relationships between step-siblings or half-siblings are even worse.
"Biological and adoptive combinations are always easier than a blended family that resulted from a set of failed or broken families," Josephson said. "The dynamics in those situations are very difficult in the sense that the children aren't all 'owned' by the same parents."
Child psychiatrists and author of "Raising Kids With Character" Elizabeth Berger told ABCNEWS.com that how parents act not only toward their kids but also toward each other matters tremendously to the relationship their children foster.
"Nasty situations are often indicative of a dynamic that really involves the whole family," Berger said.
Barbara Taylor Blomquist had already given birth to a baby girl when, three years later, she decided to add to her family — the less conventional way.
Adopting two infant boys within three years of one another, Blomquist told ABCNEWS.com that her children never had any animosity toward one another because of the adoption, and their problems were rooted in who they were as individuals and how they related to one another.
"I think the general public sees adopted children as causing more problems within families than biological ones do, and sometimes that is the case but often it's not," said Blomquist, who wrote the book "Insight Into Adoption," which stems from her experience as an adoptive mother.
"Each time we adopted a baby boy, it was our daughter's little baby brother," Blomquist said. "When you're growing up, children are children."
The problems many adopted kids have to deal with are certainly important to recognize, said Adam Pertman, executive director of the Adoption Institute and author of "Adoption Nation," who went on to say that they may not be any worse than other problems families face.
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