Lydia Fairchild (born 1976) is an American woman who exhibits

chimerism A genetic chimerism or chimera ( ) is a single organism composed of cells with more than one distinct genotype. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood ...

, having two distinct populations of DNA among the cells of her body. She was pregnant with her third child when she and the father of her children, Jamie Townsend, separated. When Fairchild applied for enforcement of child support in 2002, providing DNA evidence of Townsend's paternity was a routine requirement. While the results showed Townsend to certainly be their father, they seemed to rule out her being their mother. Fairchild stood accused of fraud by either claiming benefits for other people's children, or taking part in a

surrogacy Surrogacy is an arrangement, often supported by a legal agreement, whereby a woman agrees to delivery/labour for another person or people, who will become the child's parent(s) after birth. People may seek a surrogacy arrangement when pregnan ...

scam, and records of her prior births were put similarly in doubt. Prosecutors called for her two children to be taken away from her, believing them not to be hers. As time came for her to give birth to her third child, the judge ordered that an observer be present at the birth, ensure that blood samples were immediately taken from both the child and Fairchild, and be available to testify. Two weeks later, DNA tests seemed to indicate that she was also not the mother of that child. A breakthrough came when her defense attorney, Alan Tindell, learned of Karen Keegan, a chimeric woman in Boston, and suggested a similar possibility for Fairchild and then introduced an article in the ''

New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one. Hist ...

'' about Keegan. He realized that Fairchild's case might also be caused by

. 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 The Papanicolaou test (abbreviated as Pap test, also known as Pap smear (AE), cervical smear (BE), cervical screening (BE), or smear test (BE)) is a method of cervical screening used to detect potentially precancerous and cancerous processes in t ...

test did match. Fairchild was carrying two different sets of DNA (with one of them of being her unborn twin's), the defining characteristic of chimerism.

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References

ABC News: She's Her Own Twin
Article on Fairchild
Kids' DNA Tested, Parent Informed The DNA Is Not A Match
Article on Fairchild's case

New Scientist Article on Karen Keegan's case

Discussion on Tetragametic Humans
DNA Tests Shed Light on 'Hybrid Humans'
NPR recording. 20th-century American women 21st-century American women 1976 births Applied genetics Chimerism Living people 20th-century American people {{us-bio-stub

See also

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References