As a teenager, she said her biggest concerns were "shoes and boys." She had no reason to think much beyond herself, until reporters at the National Enquirer revealed her birth identity to her around her 19th birthday in 1989.
Her biological mother, they told her, was Norma McCorvey.
"They'd asked me if I'd ever heard of her before and I said no," Thornton, 51, told ABC News' Linsey Davis in an exclusive interview. "And they said, 'Well, she is the woman who they used to do the Roe versus Wade case. She was Jane Roe.'"
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Thornton's identity has been unknown to the public for more than 50 years. She was first named as McCorvey's daughter last month in an article published in The Atlantic.
She is speaking out now, she told ABC News, in her first on-camera interview, because "it's my turn."
"My story is my story," Thornton said.
'Oh God, everybody's going to hate me'
Nineteen years earlier, McCorvey, then 22 and unmarried, was pregnant and having already given up two babies decided she didn't want to have a third. At that time, the legality of abortion was based on state's decisions, and McCorvey was in Texas, where it was illegal.
She went on to become the plaintiff, going by the pseudonym "Jane Roe," in the case that made abortion a federally protected right.
But the Supreme Court didn't make that decision until 1973. By then, McCorvey had already given birth and placed the child, who was Thornton, for adoption.
Before she was hit with this news at age 19, Thornton said she hadn't thought much about abortion. Most of what she knew, she said, was the "Hollywood version" based on movies.
Within the scope of her family, abortion was "a non-thing," she said. Especially as someone who was adopted, she had grown up with the idea that "if a family member had a baby, they couldn't take care of it then somebody else in the family took it and took care of it."
The reporters had contacted Thornton -- without disclosing they were reporters, she said -- and said they'd tell her the identity of her biological mother at a restaurant in Seattle's Space Needle, so she went with Ruth, the mother who raised her.
After dropping her identity on her, she said the reporters asked Thornton if she was "pro-choice or pro-life." She said she told them she didn't even know what that meant.
Ruth shut down the meeting and got Thornton out of the situation. Leaving, Thornton says she completely broke down.
"My whole thinking is that, 'Oh God, everybody's going to hate me because everyone's going to blame me for abortion being legal.' You know, it's like 'it's all my fault,' is pretty much what I was thinking," she said. "And that's really hard to grasp when you're in that kind of a situation and you're just kind of like learning all of this stuff."
'She didn't deserve to meet me'
McCorvey died in 2017, and her own opinion on abortion -- if it was ever truly black and white -- went to the grave with her.
She became publicly known shortly after the Supreme Court decision and became part of the abortion rights activist movement in the 1980s, making appearances and announcing she wanted to find the child she'd placed for adoption.
But in the 1990s, McCorvey joined activists on the anti-abortion side.
That was thought to be her opinion -- until the documentary "AKA Jane Roe" was released in 2020 including a late-life interview where she said she wasn't actually against abortion. She claimed she had been paid by the anti-abortion movement to say she was.
"I think she was taken advantage of by both sides, but I think she also took advantage of both sides," Thornton told ABC News.
Thornton talked to McCorvey on the phone after the Space Needle ambush.
"It became apparent to me really quickly that the only reason why she wanted to reach out to me and find me was because she wanted to use me for publicity," Thornton said.
She never agreed to meet her biological mother in person and has "no regrets" about that, not just because of how they were introduced, but also because of comments McCorvey had made to the press about alternatively feeling guilty for placing her for adoption and wishing she'd gotten the abortion.
"She didn't deserve to meet me," Thornton said. "She never did anything in her life to get that privilege back. She never expressed genuine feeling for me or genuine remorse for doing the things that she did, saying the things that she did over and over and over again. She wasn't sorry, about giving me away or anything."
Thornton has never forgiven McCorvey and has no plans to do so, "mostly because I feel that she could have handled things a lot better," including by being "upfront" about wanting to meet her for the media attention.
"I can deal with that. I can't deal with lies and treachery and things like that. To me, that's like no, sorry, not playing that game with you. And that's all it was. It was a game. It was a game. I was just a pawn, and I wasn't going to let her do it," she said.
'I'm not going to let either side use me'
Thornton is wary of anyone trying to make her a pawn in their game. No longer 19, she has an opinion on abortion, but she keeps it "close to my chest."
"I don't really talk about that just because I'm not going to let either side use me for their advantage," she said, "because that's not me and -- you know -- find somebody else."
This particular moment is ripe for opinions with little room for nuance. Last month, the Supreme Court allowed a law to go into effect in Texas -- where McCorvey's case started -- that is a near-total ban on abortion. Later this year, the Supreme Court is hearing another case that directly challenges the decision Thornton's conception made happen.
Since that fateful meeting with the National Enquirer reporters 30 years ago, Thornton has come to terms with the fact that "the actions of Norma are not mine." The story people try to put on her, the blame she initially felt for others' feelings -- she's outgrown them.
"I had nothing to do with it," she said. "I was just a little itty-bitty thing and, you know, circumstances prevailed."
Keeping her biological identity a secret for three decades has been a weight on her, but she made a stable life for herself with a husband, career and kids of her own.
She also has been able to open up with her biological sisters. Before Thornton, McCorvey gave birth to two daughters, who were also placed for adoption. Thornton was able to connect with one of them in their early 40s.
"It was an instant bond between us," her older sister Jennifer Ferguson said in a joint interview with ABC News. "We have a lot of similarities. We both like the same colors, we both like to do the same crafts and things like that. We both have probably about the same patience level with things."
Ferguson said Thornton choosing to keep her identity a secret for so long was "a big burden" for Thornton.
"For her to have to keep that under lock and key for so many years and not talk about it, it can only hurt, and she doesn't want to do that anymore," Ferguson said. "So, yeah, I'm 100% behind her."
The two women said they talk almost daily now and have a close bond.
"I know that no matter what I do, what I say, where I go, whether if she agrees with it or not, she's going to have my back 100%," Thornton said. "She's not going to let anybody take advantage of me and she's not going to let anybody get away with anything because I'm her baby sister."