DNA testing is not a simple matter

There are some instructive points in this cautionary story of human chimeras:

"...a Washington state woman found out that pregnancy was not enough to prove motherhood; DNA testing indicated that she was, in fact, not the mother of her own children – so who was? During the course of a desperate battle to retain custody of her three children, it was discovered that her twin was the real biological parent. The twist? She, 26-year-old Lydia Fairchild, was her own twin."...

In order to qualify for financial assistance in supporting her young family, Fairchild was required to undergo DNA testing to prove that she was the mother of children for whom she was claiming... To her horror, the young mother was informed that she would be the subject of an investigation into possible welfare fraud as the DNA tests had revealed no genetic link between her and the children she claimed were hers...

Derived from the name of a strange hybrid creature, the Chimera of Greek legend, this condition had been documented just 30 times throughout the world. Those rare individuals, dubbed “Chimeras”, had started out as twins; in the early stage of pregnancy, one of the twins had merged with – been absorbed by, one could almost say – the other twin.

The cells of the consumed twin, however, did not disappear and remained alive in one concentrated area of their sibling’s body. In essence, a human chimera is one person made up of two separate sets of genetic material; they are, in fact, their own twins...

Some sixteen months later, after enduring the harrowing prospect of even pregnancy being no proof of motherhood, Lydia Fairchild found the case against her dismissed. Her attorney, Alan Tindell, reflected on the dire consequences of oversight in the testing of DNA. “People go to death row because of DNA tests,” he said, “people are released from death row because of DNA tests.”

A hat tip to reader talcumX for bringing the article to my attention.