It's been 10 years since Mamma Mia! [1] first hit theatres, and the film is still near and dear to fans' hearts [2]. While we still can't get enough of all the catchy songs [3], there is one thing about the film that still bugs us after all this time: who is Sophie's biological father? In the film, there are three possibilities — Harry, Sam, and Bill [4] — but we never actually get a confirmation. After each of the men form a strong bond with Sophie, they ultimately decide that they don't want to know the true paternity and agree to all be one-third of a father to her. Although the film never reveals who Sophie's dad is, fans do have a pretty convincing theory. Before catching Mamma Mia! Here We Go Again [5] in theatres on July 20, see all the evidence we have about who Sophie's biological father is.
Harry
While Sophie certainly takes after Harry with her love of singing, there aren't any other convincing arguments for why he's her biological father.
Sam
Throughout the first film, Sophie seems to have the strongest connection with Sam, but there isn't much evidence that he's her biological father either. However, he does eventually become her stepfather after he marries Donna, his one true love.
Bill
While it's never confirmed whether Bill is Sophie's biological father, there are a few clues throughout the first movie that suggest he is. During his first conversation with Sophie, we learn that she is actually named after his great aunt, Sophia. In another conversation at Sophie's bachelorette party, Bill asks how Donna was able to afford her place and Sophie reveals she got the money from his aunt Sophia. Bills then adds, "I always heard her money was left to family." Of course, since Donna herself doesn't know who the father is, Sophie's name wouldn't really be any indication of her paternity.
Though, there is one more clue that Bill could be Sophie's biological father. In the first film, Sophie was supposed to sing "The Name of the Game" with Bill, but it was cut from the theatrical release. If the scene would have stayed in the film, it would've been the only duet Sophie sang with one of her potential fathers.