A woman found out she was not the biological mother of her children after separating from her husband when pregnant with her third child.
Lydia Fairchild then had to fight in court to prove the children she gave birth to were her own and not abducted - by proving she was a 'chimera', and carried two sets of DNA - one from her onborn twin.
The condition gives the people who have it two blood types – which meant when Fairchild applied for benefits in Washington state, a DNA test showed she was not the mother.
Approximately one in eight single childbirths are thought to start as multiple pregnancies and occasionally cells from the miscarried siblings are sometimes absorbed in the womb by a surviving twin.
"I knew that I carried them, and I knew that I delivered them. There was no doubt in my mind," Fairchild told ABC News.
Fairchild was reportedly accused of welfare fraud and illegal surrogacy. She claims social services told her: "You know, we're able to come get your kids at any time."
"I'd sit and have dinner with my kids and just break out crying. They would just look at me like, 'What's wrong.' They'd come get me a hug, and I couldn't explain it to them, because I didn't understand," Fairchild said.
Even after Fairchild gave birth to her third child a government witness was present at her birth - but they believed that she was carrying the baby for someone else.
After three court hearings, Fairchild's lawyer heard about a similar case where a child did not match her mother's DNA - due to chimera. Tests were ordered that confirmed she had the condition, and all charges were dropped.
A similar case took the world by storm after a man's son had the DNA of his unborn twin and not him.
Most chimera suffrerers don't even know that they are suffering from the condition. Sometimes, a chimera child's eyes are different colour or they might have patches on their skin.