Lydia Fairchild is a British woman who exhibits chimerism, with two different sets of DNA present in her body. She was pregnant with her third child when she and the father of her children, Jamie Townsend, separated. When Fairchild applied for welfare support in 2002, she was requested to provide DNA evidence that Townsend was the father of her children. While the results showed Townsend was certainly the father of the children, the DNA tests indicated that she was not their mother.
This resulted in Fairchild's being taken to court for fraud for claiming benefit for other people's children or taking part in a surrogacy scam. Hospital records of her prior births were disregarded. Prosecutors called for her two children to be taken into care. As time came for her to give birth to her third child, the judge ordered a witness be present at the birth. This witness was to ensure that blood samples were immediately taken from both the child and Fairchild. Two weeks later, DNA tests indicated that she was not the mother of that child either.
A breakthrough came when a lawyer for the prosecution heard of Karen Keegan, a human chimera in New England, and suggested the possibility to the Fairchild's lawyer, Alan Tindell, who then found an article in the New England Journal of Medicine about Keegan. He realised that Fairchild's case might also be caused by chimerism. As in Keegan's case, DNA samples were taken from members of the extended family. The DNA of Fairchild's children matched that of Fairchild's mother to the extent expected of a grandmother. They also found that, although the DNA in Fairchild's skin and hair did not match her children's, the DNA from a cervical smear test did match. Fairchild was carrying two different sets of DNA, the defining characteristic of a chimera.
- Yu, Neng; ; et al. (16 May 2002). "Disputed Maternity Leading to Identification of Tetragametic Chimerism". New England Journal of Medicine 346 (20): 1545–1552. doi:10.1056/NEJMoa013452. PMID 12015394.
- Rowlands, Letitia. "When your unborn twin is your children's mother". Essential Baby.
- ABC News: She's Her Own Twin Article on Lydia
- Kids' DNA Tested, Parent Informed The DNA Is Not A Match Article on Lydia's case
- The Stranger Within New Scientist Article on Karen Keegan's case
- Genetic Mosaics Discussion on Tetragametic Humans
- DNA Tests Shed Light on 'Hybrid Humans' NPR recording.
- Mayne, Eleanor (March 5, 2006). "The mother with three children who don't share her DNA - and why her astonishing story will throw doubt on the 'foolproof' evidence in thousands of court cases". The Mail on Sunday, London. pp. 18–19.