The Kindred and the Gender Bender
Mulder and Scully investigated the Kindred after a bizarre series of murders in which victims of both sexes had been found dead shortly after sex, and in which the suspect seemed both male and female. It was later discovered that the Kindred were able to not only change gender at will, but that they could produce enough sexual pheremones through touch to seduce their victims before sending them into shock and death.
Mulder would go on to discover that the Kindred engaged in a sort of regeneration ritual - involving a local white clay - in the cave below their large barn. It was here that deceased members would seem to return to life.As it turns out, when Mulder and Scully came looking for them, they found they had abandoned their homes and vanished, leaving behind only a crop-circle. This seems to show that the Kindred are really members of an Alien Race. The Kindred imitated the ways of the anabaptist-style communities (Amish, Mennonites, Hutterites, etc.) in order to be left to their strange customs and experiences. The fact that a woman, Sister Abigail, was the Kindred's leader gave away their difference, the secluded anabaptist communities being led by men. Their ability to switch gender is evocative of the Alien Bounty Hunter's ability to take on any human appearance he wishes, male or female.