It doesn't lie. So who are you?'

[question everything]

Full title

It doesn't lie. So who are you?': What happens when DNA tests show a woman is not the mother of the child she gave birth to?

DNA is often considered the ultimate indicator of our identity — a foolproof way to determine our origins and how we connect to our parents and previous generations of our family. But in this excerpt from "Hidden Guests: Migrating Cells and How the New Science of Microchimerism Is Redefining Human Identity" (Greystone Books, 2025), author and science journalist Lise Barnéoud explores an unusual case that exposes the limitations of DNA testing, when a maternity test suggested a woman was not the mother of the children she gave birth to.

Lydia Fairchild was 26 years old when she applied for welfare benefits to help her raise her two children on her own. As part of the application process, she had to undergo a maternity test. A few weeks later, she was called into a meeting with social services, where they accused her of not being the mother of her children. "At first, I kind of laughed … But they were serious. I could just see the seriousness in their faces," Fairchild said. "DNA is 100% foolproof, and it doesn't lie," a social worker told her. "So who are you?"

At first, Fairchild was suspected of attempting to defraud the welfare system by inventing children. The state prosecutor launched an investigation and quickly confirmed that two children did indeed live with her. Could she have kidnapped them? Fairchild showed them photographs of herself pregnant. Her mother, her children's father, and her obstetrician all testified to the fact that she had given birth.

(snip)

Fairchild was pregnant with her third child at the time, and the judge asked that both mother and child be tested immediately after birth. And the impossible happened: Fairchild's third child, just emerged from her womb, was not her son either — genetically speaking.

At last, a lawyer agreed to help her. Alan Tindell asked Fairchild about her life, her relationships with her siblings, and her relationship with the father of her children. "Given her answers, I finally decided to believe her," Tindell explained. He soon came across a scientific article describing Karen Keegan's case and contacted the team in Boston to ask them to examine Fairchild. They first tested Fairchild's blood, but they found only one cell type, just as they had for Karen Keegan. They moved on to cells from her skin, hair, and cheek: still nothing.

Until the day they performed a cervical smear. There, they found cells with a different DNA, a DNA that matched Fairchild's children as well as her mother. They concluded that the second DNA must have come from a vanished twin sister. Fairchild could finally breathe. But how would her story have ended without Karen Keegan?

https://www.yahoo.com/news/articles/doesnt-lie-happens-dna-tests-150629304.html

[progressoid]

1. Radiolab did a show about Karen Keegan's case and chimeras.

https://radiolab.org/podcast/91596-so-called-life

https://radiolab.org/podcast/91596-so-called-life/transcript

[eppur_se_muova]

2. Truly ... ""There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy."

(Hamlet, Act 1, Scene 5)

There are times when even science can't anticipate every trick Nature can throw at us, but at least it doesn't really claim to, unlike dogmatic belief systems like religion and partisan politics. Those who harness scientifically-derived methodology for social, political, or commercial purposes must keep this in mind. Claiming that a woman's child is not her own is an exceptional accusation, requiring exceptional evidence. Here, the evidence was a little too routine (in modern usage) to carry that burden with full confidence, so alternative explanations had to be explored. I wonder how many women may not have gotten that second chance.

Kudos to that judge for recommending testing of her third child. It seems kind of obvious, but not every judge would have accepted the argument that it was necessary.

[lastlib]

3. Fascinating read!

Wow, I never imagined something like this would be possible!

Thanks for posting!