In 2002, Washington mother Lydia Fairchild sought public assistance and soon faced an almost impossible accusation. DNA testing showed that the father of her children was genetically related to them, but Fairchild apparently was not. She had carried and delivered them, yet the laboratory results contradicted that basic fact. The Lydia Fairchild chimerism case became a striking example of how reliable science can mislead when biology is unusually complicated. What happened next forced a court to confront a question that sounds like science fiction: Can one person carry two distinct sets of DNA?
