This is Lydia Fairchild, and she is one of the rare people in the world known as human chimeras. When a fertilized egg meets another fertilized egg in the womb it has 2 choices: develop separately into fraternal twins, or absorb the competition. Chimeras occur when the twin is absorbed but doesn't die, instead continuing to live in your body. Thus one person carries 2 different set of genes, with random organs having your twin's DNA. Anyone could be a chimera without knowing it.