From my email:
"Gender Bender" is the fourteenth episode of the television series The X-Files. The show centers on FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) who work on cases linked to the paranormal, called X-Files. In this episode, they investigate a series of murders following sexual encounters, and soon discover that a member of a religious sect living in Massachusetts may be responsible—and may not be human. Premiering on the Fox network on January 21, 1994, it was directed by Rob Bowman and featured guest appearances by Brent Hinkley and Nicholas Lea. The episode was inspired by producer Glen Morgan's desire for "an episode with more of a sexy edge"; however, the writers found it difficult to write a story that showed sex as scary. This difficulty led to the introduction of an Amish-like community as well. "Gender Bender" had mixed critical responses, facing criticism for its abrupt deus ex machina ending. Academic analysis of the episode has placed it within a science-fiction tradition that attributes a powerful, supernatural element to physical contact with aliens. It has also been seen as reflecting anxieties about emerging gender roles in the 1990s.