From X-Files Finis Romantics Society -

In One Son-- Marita is back, and not happy to have been made the Consortium's guinea pig.

One unconfirmed rumor: By the end of One Son, Mulder and Scully are back big time in the basement.

(11/22/98) Here's some episode 12 info from Jesse on the AOL message boards

Marita is back and boy is she mad. Spender's mom is back and boy is Spender mad. Mrs. Mulder is back and boy does she have a secret. It's called "One Son"