Well what if Voldemort had a daughter called sally Riddle, but she was sorted into Ravenclaw, he declared her a disappointment to the Riddle name. He soon over looked that but what if she got married to a man she thought was a muggle but turned out to be a god of the sea, Poseidon. Just imagine if they had a son they named Percy Jackson, who was a well known demi god! What if they were told they needed to send Percy to Hogworts!