On the original CSI there was an episode years ago that depended on the killer being a chimera, someone who actually had two genomes in his body so a cheek swab test had different results than a blood test. It turns out that this condition and a related one aren’t nearly as rare as once believed. Researchers still aren’t quite sure how widespread this condition is, though there is speculation that most women who have had children have some of their genetic structure still somewhere in their body. This has the potential to have major repercussions in medicine and medical research.