"We haven't been able to bring ourselves to share with her who he is. I'm not ready to share that with her. I think because as his mother and her mother I have that guilt that even though I'm so happy I made the decision I made, she came after him. And that's going to be hard to explain not only to Abby, but to Sam. That's the hard part for me," Elliott said, fighting back tears.
Although the family openly receives photos of Sam from his adoptive family, Elliott says Abigail thinks the boy in the photos is either a friend or a relative.
Eventually, Elliott says, she will have to overcome her guilt and tell Abigail. But not today.
Even if some take their time to tell, Belkin said, it's common for many children to feel betrayed.
"Some might say, 'If my parent never disclosed this major situation to me, what else may they have withheld from me?" said Belkin. That may bring anger, resentment, and mistrust, he said.
Winfrey has long considered her best friend, business partner, and confidante Gayle King as the "sister everybody would want," she told ABC News' Barbara Walters in a 20/20 exclusive interview last month.
And although Winfrey wanted to meet her biological sister Patricia, she said she was unsure what to do next.
"Some say you can't move on until you know the truth," said DeMuth. "But you have to ask, so what if you know the truth? You still have the decision to make of either moving forward or not."
Twilla Fontenot, 48, of Dallas, was 16 years old when she came home one day to find a stranger sitting at her family's kitchen table, whom her mother introduced as Fontenot's half-brother.
"People react to situations differently," she said. "When you have chaos in the household, when you have one more thing thrown at you, it just didn't soak in for me."
Until then, Fontenot had no idea her father had a son from a previous marriage. And it wasn't until nearly 20 years after that brief introduction that she decided to reunite with her half-brother.
"I was curious to know what he would be like. For some reason I really truly was hoping that my father would build a connection with his son," said Fontenot.
But it wasn't easy to build a relationship with her half-brother. And although she still sees him occasionally, she says she's unsure whether it brought the closure she thought it might. She feels much closer to her other siblings, with whom she was raised.
"When you haven't been raised with a sibling, there's not those connections, those memories and experiences you go through in life," she said.
And according to Belkin, although Winfrey was introduced to a blood-related sister, she may also feel more of an acquaintance or, at best, a friendship with Patricia.
"Siblingship is an emotional feeling as much as it is biological feeling. You can have a sibling relationship with someone who's not related with us and we can have a sibling whom we feel no relationship with," said Belkin.
While Winfrey seemingly embraced her sister within a few months of knowing, Belkin cautions others to take as much time as they need to decide how they will proceed once they know the truth.
"People love Oprah and care about her, and I think you know there's going to be pain involved," said Belkin. "And what she can do is what she's always done -- use this to help other people."