I'm not sure what you're talking about. I created a Sim and from him created parents via the genetic symbol. From the parents I then created his siblings. If you're talking about creating a clone (twin) of a Sim, I have done that when the born in game twins weren't identical, as they were supposed to be. Even then I don't think I realized any unique relationship from it. Sorry, I'm no help at all. I just abhor it when people read a thread but don't offer anything. Best of luck. I hope somebody who understands the question will come along and answer it. :)