Conventional wisdom--and a considerable amount of psychological research--would have you believe that adopted children have more problems than those who grow up with their biological parents. Not so, suggests a new study.

Psychologist DiAnne Borders, Ph.D., of the University of North Carolina at Greensboro, asked groups of adoptive and biological parents to evaluate their children's development and found that they rated their offspring essentially the same.

Non-adopted kids were just as likely to be unhappy or anxious, to lose their temper or to bully their classmates. At the same time, adopted children were judged as cheerful, sociable and responsible as their non-adopted peers.

So what accounts for earlier studies' findings? Previous researchers simply found what they were looking for, says Borders: they assumed that adoptive families were deficient and asked questions that confirmed their bias.

What's more, she says, their entire approach was misguided: what matters is not a family's form but its functioning. To that end, researchers should focus not on finding problems in adoptive families but on identifying ways they can handle their unique issues and build on their distinctive strengths.