The technical definition is sexual attraction toward the unknown, or that which is different.
Those who identify as Xenophiliacs typically feel sexual desires for one or more fictional races of aliens, mutants, or other sentient beings that are not human in movies, books, etc
It is not limited to any gender or sexuality.
Girl one: Damn - did you see Turtles in Time? There were Raphaels everywhere!
Girl two: Ewwww! He's a mutant freak!
Girl one: You know I'm a xenophiliac. Besides, he's better looking than your boyfriend!