Trivia: Scully's father, Scully's older brother, and the man Mulder thought was his biological father were both named William. (The father who raised Mulder went by "Bill, " as did Scully's brother.) Mulder's actual biological father, Cancer Man, was played by William B Davis (who also goes by "Bill"). Scully and Mulder's son was also named William (before being adopted and having his name changed to Jackson).