I thought that same thing! How many paternity tests gone wrong!! And how many innocent people in jail, or how many gone free when they shouldn't have. A whole new can of worms I guess the legal system really doesn't want to think about it. Add in a whole lot of 'disappearing twins' that are on ultrsound one minute and gone the next, well maybe this is where they go! I had a disappearing twin on my ultrasound once, but then lost the other so my own little chimera didn't happen. From what I understand sometimes the other dna is only on the inside in internal organs.