I think the term "gender fluidity," in itself, may be inaccurate. I don't know too many GLBGQXYZ's that just woke up one morning and decided to shift genders. Most of these folks, as far as I can gather, felt "confused" about their gender from a very early age. That is to assume, however, that the etiology of gender identity is always endogenic in nature. Which I am not entirely convinced that it is.