David Duchovny was anxious during filming due to the imminent birth of his first child, who was born two days after filming concluded.
In the opening teaser, footage of the cavemen walking through the snowstorm is from The X Files (1998).
The Bible scripture shown when the camera pans in is Genesis 1:28, in which God tells Adam and Eve to "be fruitful and multiply" and to "subdue the Earth."
Beach scenes were shot at the same beach as the opening scenes from Grease (1978), the Leo Carrillo State beach in Malibu.
While Mulder exhibits abnormal brain activity and psychic ability and experiences headaches, Scully will be revealed to do the same in the Season 11 premiere My Struggle III (2018).