<P> The show centers on FBI special agents who work on cases linked to the paranormal, called X-Files; this season focuses on the investigations of John Doggett (Robert Patrick), Monica Reyes (Annabeth Gish), and Dana Scully (Gillian Anderson). In this episode, Doggett finds a strange, disfigured man (Chris Owens) in the X-Files office and, on his whim, they test his DNA . They learn that the man shares DNA with Fox Mulder (Duchovny), and may possibly even be him . The answers become even more surprising when Scully's son, baby William, is put on the line . </P> <P> "William" marked the return of David Duchovny to the series, after his departure following the eighth season finale "Existence". The genesis for the episode was a storyline Duchovny had developed during the series' eighth season; he originally pitched an idea featuring a mysteriously disfigured person introducing himself to Scully and admitting that he possessed a connection to Mulder . Chris Owens, whose character Jeffrey Spender had previously been killed off in the sixth season episode "One Son", was asked to return to the series for the episode . </P> <P> In the teaser, a couple, the Van De Kamps (Adam Nelson and Shannon Hile), adopt Dana Scully's (Gillian Anderson) infant son, William (James and Travis Riker). The episode then jumps back a week . Scully takes William out of her car while an unknown man (Chris Owens) watches them . Later, John Doggett (Robert Patrick) is attacked in the X-Files office by the same man . After a struggle, Doggett subdues him . His face is revealed to be horribly scarred . </P> <P> Later, Scully speaks with the man . He claims he received his burns due to alien testing and that he knew Fox Mulder (David Duchovny). He further elaborates that he was sent to the FBI to retrieve certain files . Scully suspects the man is lying, but asks to examine his burns to investigate his strange claims . He notes that they are the result of an injection that failed to transform him into one of the aliens . The man claims a new conspiracy has formed after the previous one was destroyed; the new one being hidden within the government and the conspirators involved being alien . Doggett theorizes that the man is actually Mulder . Scully takes the man to her house to give him the files he seeks . Suddenly, William begins to cry, only to be quieted when the scarred man picks him up . Meanwhile, Walter Skinner (Mitch Pileggi) meets with Doggett and the two discuss the idea that the man is actually Mulder . Skinner points out the inconsistencies in Doggett's reasoning, but a DNA test is undertaken anyway . </P>

Do mulder and scully have a kid together