No baby bump pictures. No friends who saw the baby bump. No hospital records (but then there's that pesky birth date again). No proud mama, papa, and grandparents pictures of the newborn. The mysterious "USA Anna" and the Seattle "Anna" and the Dunham's muslim cousins who claim zero's mama died....
But then again, if he is Stanley's long wanted son, why would Madelyn agree to such an arrangement? Why would SADO agree to such a crazy idea? There were much easier and much more socially acceptable arrangements that could have been made. Even if SADO wasn't into what was socially proper, a baby would interfere greatly in a teenage girl's life.
IF the baby was fathered by Gramps and the black barmaid Barry mentions in Dreams, it’s possible SAD was not told the truth. We don’t know where Madelyn was then? How do we know she didn’t go away for 3-4 months. You can hide a pregnancy until around 6 months. I KNOW SAD is not the mother. I would stake my life on it. The question is... who is the real mother? SAD didn’t give 2 sh*ts about Barry. She shipped pawned him off on her parents in 1970, the same year FMD got a divorce and his wife moved out. There is a connection there and also a connection as to why Sr. visited that one time. Figure that out and therein lies the answer IMO.