CHICAGO (AP) — Oprah Winfrey recently learned she has a half-sister — a Milwaukee woman who was put up for adoption by Winfrey’s mother nearly 50 years ago.

On “The Oprah Winfrey Show” that aired Monday, a sometimes-emotional Winfrey introduced a woman she identified only as Patricia, explaining how the woman’s years-long search for her family culminated in a meeting with Winfrey on Thanksgiving Day of last year.

The discovery is “the miracle of all miracles,” Winfrey told her audience.

Winfrey said she was stunned to learn about the sibling, telling her audience that when Patricia was born in 1963, Winfrey was 8 years old and living with her father. She did not even know her mother was pregnant.

Patricia said she had tried years ago to learn the identity of the woman who gave her up for adoption, and only started to try again a few years ago at the insistence of her two adult children, who also appeared on Monday’s show.

Patricia said she feared her search would be fruitless after she got a telephone call from the state adoption agency, which reported that her birth mother had been contacted and did not wish to meet her.

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But, coincidentally, on the local news that day, she saw a story about Winfrey’s mother, who described how two of her children had died. Those details matched information Patricia had seen in adoption papers, which indicated she had two sisters and a brother, and that only the older sister was alive.

Winfrey’s mother, Vernita Lee, also disclosed that one of the deceased children was named Patricia.

“The hairs on the back of my neck stood up,” Patricia said. “Because I knew one of my siblings and I shared the same name.”

Later, she found more details that matched, including the fact that Winfrey was born in 1954, the same year as the woman Patricia knew was her surviving sibling.

Winfrey, who said DNA tests confirmed that the two are half-sisters, met with Patricia and their mother in a pre-recorded segment of the show.

Lee, who recently suffered a minor stroke, said she never told Winfrey about her half-sister, “because I thought it was a terrible thing for me to do, that I had done, gave up my daughter when she was born.”

Winfrey said documents from the girl’s birth reveal that Lee gave up the baby for adoption because she did not think she could get off welfare if she kept the child.

“I made the decision to give her up because I wasn’t able to take care of her. So when I left the hospital, I told the nurse I wasn’t going to keep the baby.”

Winfrey said she was particularly stunned by the news because of the way it came out. She said Patricia had known since 2007 that the two were related, but she never attempted to profit off her discovery or contact the press, even as she tried unsuccessfully to contact Winfrey, her mother or others in Winfrey’s family.

“She never once thought to sell the story,” Winfrey said, describing how she felt betrayed by other relatives who sought publicity or money.

Patricia said she didn’t consider revealing that she and Winfrey were half-sisters to anyone but Winfrey, explaining that she did not want to hurt Winfrey.

“Family business should be handled by family,” Patricia said. “It couldn’t be handled by anyone else. That’s not fair. It wouldn’t be fair to you.”

Winfrey recalled how her other sister revealed to the press years ago that Winfrey had had a baby when she was a teenager. The baby, Winfrey has said, died shortly after birth. And she talked about putting her sister in rehababilitation twice for drug addiction, but that her sister ultimately died.

“It feels to me like you are Pat on her very best day,” Winfrey told the woman. “You are what she wanted to be without the drugs.”

Copyright 2011 The Associated Press.