DNA isn't perfect... if you're a Chimera
"Lydia Fairchild couldn't prove her kids were her own through a simple DNA test. She fought in court to keep her children. Finally, doctors told her she had a rare disorder, chimera."
"Jane was a puzzle to doctors. She needed a kidney transplant, but her naturally conceived sons could not donate - because they were not biologically related."
And for the scientists amongst us (hi there bro!!):
"Two clonal genetically different populations of precursor cells begin to proliferate in a transvere direction, starting from the primitive streak each side of the neural tube. The transverse clonal proliferation of cells interferes with the longitudinal growth and increasing flexion of the embryo.These complex movements result in the bizarre pattern of the lines of Blaschko"