The unlikely story of a human chimera or a woman who failed a DNA test. This failed to prove she was the mother of the child she knew she had given birth to.

When DNA CAN Lie – Lydia Kay Fairchild

Lydia Kay Fairchild was twenty-one when she had her first baby. Despite being separated from the baby’s father, Jamie Townsend, she and Jamie had a second baby a year later.

Another year on and and she became pregnant for the third time after which she and Jamie split up again. With no steady work and unable to support herself and the children she applied for state benefit.

Lydia Kay Fairchild Human Chimera
Lydia Kay Fairchild

Her world was about to be turned upside down. The State Prosecutor’s Office required DNA tests from Jamie to prove that he was the father of the children and, as a matter of course, Lydia was also tested.

In December 2002 she received a phone call from the prosecutor’s office asking her to come in for the results. This was unusual and it soon became apparent why.

The results confirmed that Jamie was the father but they also revealed that Lydia was not the mother. A normal DNA test proving a mother-child link would show a 50% match between their DNA patterns. Yet Lydia’s DNA showed no match at all.

Invetigation of the State Prosecutor

The state prosecutor started an investigation. Lydia and her family feared that a case of welfare fraud was being mounted against them.

Suspicion spilled over to Lydia’s estranged partner, Jamie Townsend. He was interviewed and accused of fathering the children with another woman. The family knew they were under suspicion. Even the medical evidence they had of the children’s births didn’t seem to count.

obstetrician Leonard Dreisbach
Dr Leonard Dreisbach

Dr Leonard Dreisbach, Lydia’s obstetrician said: “I’ve been doing this long enough to recognise when someone is giving birth right in front of you.

The babies are footprinted at the time, in the delivery room, and the cards are filed as proof of the birth. This may be an older technology but it has worked well in the justice system for many years.”

Lydia, pregnant with her third baby, faced continued questioning by the state prosecutor and was, at one point, threatened with a lie-detector test, which she would have welcomed. All of this culminated in a summons being issued. Lydia was being taken to court.

Karen Keegan

Meanwhile, 2,500 miles away in Boston, Massachusetts, Karen Keegan a 52 year old teacher was confronted with the same startling information.

However, according to DNA testing her children were not hers. Karen had been in urgent need of a kidney transplant and she and her family were tested to find a matching donor.

Just as in Lydia’s case, there was no genetic match between Karen and her eldest two boys.

During her treatment, Karen met transfusion specialist Dr Lynne Uhl who became intrigued by her story.

Dr Uhl arranged to have Karen and her boys tested again. When her youngest son was tested for the first time, he was found to be a match!

The doctors sought advice from senior colleagues and it was one of these who suggested Karen might be a human chimera. A human chimera is someone who has two completely different genetic identities; two sets of DNA.

Human Chimera

It is believed that a human chimera is formed when two fertilised eggs fuse together, early in their development.

Human Chimera Karen Keegan
Karen Keegan

To prove Karen was a human chimera, doctors had to find the second DNA somewhere in her body. Her doctors got funding for a dedicated research project. They enlisted the help of immunologists at the American Red Cross and Harvard Medical School.

Tests on her hair and skin samples proved fruitless, so doctors decided they needed to take samples from her internal organs. Dr Uhl had been fortunate and told us: “She’s had some prior surgery. And, we were able to retrieve specimens from the pathology department. In particular the thyroid tissue and tissue obtained from her bladder.”

The tests were painstaking and it would be months before Karen’s diagnosis of human chimera could progress. Karen’s doctors were determined to understand the mystery of her DNA.


It was very different for Lydia Fairchild, No-one dealing with her case had even heard of chimerism and she was about to go to court to establish the parentage of her children. She could not even get a lawyer to take her case as they all considered the DNA evidence irrefutable.

Father Jamie Townsend
Jamie Townsend

While the investigation was proceeding, the court wanted to appoint guardians for each of the children.

Based on the existing evidence, the judge agreed that Lydia was not their biological mother. This was the worst possible outcome for Lydia and Jamie.

Unravel Pregnancy Mystery

Lydia Kay Fairchild was now heavily pregnant with her third child. The judge realised that this latest pregnancy could provide vital clues to help unravel the mystery. He ordered that someone be present at the birth to act as witness and to take blood samples immediately after the birth.

These latest DNA test results were arresting. They showed no match between Lydia Kay Fairchild and the baby. It was what the family wanted to hear and Lydia finally got a lawyer to help her.

Alan Tindell, Lydia’s attorney is aware that the prosecution are considering the possibility that Lydia is a surrogate mother.

The mother of a child that had been an implanted fetus would have no genetic relationship.

The abduction of the children is another possibility the prosecution must consider.

It seemed that only science could provide the answers. By an extraordinary chance it did, when the state prosecutor stumbled across a new lead for the case. The deputy prosecutor had found an article in The New England Journal of Medicine about chimerism.

Finally. someone thought to ask the question “Could Lydia be a chimera?”

Lydia and her attorney went back to court where the judge agreed to postpone the hearing while they tried to find out more.

A Major Breakthrough

By amazing chance, the stories of Lydia Kay Fairchild and Karen Keegan now met. Karen Keegan’s doctor had written a paper in a medical journal. In it he had documented a major breakthrough.

Karen explained that her mother and both of her brothers had donated blood. These family blood records were to prove to be key to her case.

Comparing the DNA from family members led to a bizarre result. It looked as if Karen’s sons were descendants of her husband and her brother!

Having established that the boys were members of this family and carried Karen’s father’s DNA, it still remained to find the DNA in Karen. Finally the doctors struck gold. Testing the thyroid tissue revealed the missing DNA. Further testing showed that, in fact, both sets of DNA were present in all of her tissues but one set was more dominant than the other.

Doctors at the Beth Israel Hospital agreed to investigate Lydia’s DNA. After her lawyer had approached them.

What the scientists quickly established was a DNA link between the children and Lydia’s mother. Just as with Karen, the DNA was in the larger family. Lydia needed to prove that she was the real mother and that she was a human chimera. Her medical records and the scientific findings helped prove the case.

Townsend Kids
Lydia and Jamie’s Children

The court concluded that Lydia Kay Fairchild was the real mother and Jamie Townsend the father of the children, sixteen months after the first DNA result had come in. Everyone involved in Lydia’s case recognised it’s dramatic implications. In the first court hearing the judge openly wondered how far DNA tests could be relied upon.

Critical DNA Tests

Alan Tindell elaborated: “The courts rely on these tests to a great degree. People can go to death row because of DNA tests. ”

DNA testing is hugely influential in criminal cases. Forensic scientists may spend many hours looking for a DNA match. What if the criminal is a chimera?

It was not until Lydia Kay Fairchild had a cervical smear that the elusive DNA was found.

This led to speculation that Lydia may be chimeric only in her ovaries.

Both Lydia and Karen could have gone through life never knowing that they were human chimera if they had not undergone DNA testing. How many more chimeras exist and simply go undetected?

External Links

Lydia Kay Fairchild – Wikipedia Page

3 Human Chimeras That Already Exist

How a man’s unborn twin fathered his child

The Chimera Secret

The Family Tree Guide to DNA Testing and Genetic Genealogy

Human Chimera DNA Lie False

Leonard Dreisbach Jamie Townsend DNA Tests

Lydia Kay Fairchild Karen Keegan

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