We don't know where we really came from..

None of us have ever met our great great grandparents. Hardly anybody has any knowledge of what their names were, what they looked like, what they acted like, where they lived, what they did for a profession.. but we are all a direct product of their bloodline. For all we know, we could look EXACTLY like one of them and we would never know. Imagine seeing a photo of your great great grandmother or grandfather from the early 1800s and realizing that you look like their twin, just in alternate reality.. Just like in Back to the Future how Marty looked exactly like his great grandfather except he had a different hairstyle. What if we are the reincarnated soul of somebody from our bloodline who passed away right before we were born.. What if they were lingering in purgatory until a new baby from their bloodline was born and that's when they had their memory erased and were put into the body of their great grandchild..