Identical twins separated at birth are the errant thread that unravels the whole sweater. When they invariably discover each other they have the same dog, same car, similar looking husband, and basically the same vocation. This makes people very uncomfortable because it sounds like eugenics and that's Nazi shit. Don't worry kids. You can concede that we are 80% determined from birth without giving up free will and accusing everyone down on their luck of being born that way.