Wiley said that while 25 years ago many parents hid the truth from their adopted children, it's less common to do so now. It's even less common, Wiley said, to lie to your children that they are adopted when they really aren't.
"Over time the shame factor [surrounding adoption] has diminished," Wiley said. "For birthparents and adopting parents it's considered more acceptable to adopt or relinquish children, so society is a bit more compassionate."
Several psychologists told ABCNEWS.com that Applegate's situation is quite unusual, and that there is no research about the long-term effects that could result in falsely telling your child he or she was adopted.
Academy Award-winning actress Loretta Young experienced almost an identical situation to that of Applegate and her mother. Young gave birth in 1935 to the love child of Clark Gable, and because she was unmarried she gave the baby to an orphanage.
Later, Young adopted the baby girl, according The Associated Press.
"People do unusual things when they're stigmatized," said Adam Pertman of the Evan B. Donaldson Adoption Institute. "The genesis of this was this young woman was stigmatized and she dealt with it in some way that was acceptable so she could live within the culture she was in."