The defining question of The X-Files have always been “Is the truth out there?” But the rejuvenated-from-the-dead Season 10 asked a different question: “Where is William?” Remember, he was the son who Scully and Mulder gave away in order to keep him safe. Now stars Gillian Anderson (Scully) and David Duchovny (Mulder) say we’re finally going to meet the missing young Mulder.
According to TV Line, Anderson said the boy “looks like a normal kid,” which refers to the fact that he may not be as normal as he appears. As you may recall, Scully was abducted—a situation arranged by Cigarette Smoking Man—back in Season 2 and injected with alien DNA. This means William is part alien on his mother’s side.
Interestingly, Duchovny said that the (currently unrevealed) actor who plays William doesn’t take after either of them in looks. “He resembles two people that aren’t Mulder and Scully. And when you read this back [after watching the episodes] you’ll figure this out.”
Oh gods, does that mean William isn't his son? Does that mean he's going to be another son of the Smoking Man, aka CGB Spender? And perhaps X-Files’ former X-filer Monica Reyes? It’s impossible to say. We only know that we need to keep watching.
The truth will be out there, eventually. We hope.