Sex to Die For by Sarah Stegall copyright © 1995 by Sarah Stegall Written by Larry and Paul Barber Directed by Rob Bowman Watching this episode of “The X-Files” is a little like catching and eating soap bubbles on a summer afternoon: pleasant, pretty, but not very filling. The surface is iridescent with color, style, and flash, but the center is empty. Given that Mulder and Scully themselves account for a fairly high level of hormones, “Genderbender” is curiously asexual, almost virginal. From “The Creature From The Black Lagoon” to “Rocky Horror Picture Show” to “Species”, alien sex is a…