Actually, it seems to me that understanding the "cause" of transsexuality could be very important. Perhaps not so much at the level of individual personalities, but rather at the much more intriguing level of nature and the evolution of all life on this planet. Nature is no slouch; she will always seek and discover new ways to restore balance on every level... environmental balance, balance between the various forms of life, energetic balance. I feel a very strong knowing that you and me and all those that are like us are nature's answer to some need, a need that we have yet to identify. The sooner that we identify why we are as we are, the more likely we are to be active, conscious participants in our purpose for existing.
Make no mistake; gender variant people, as a collective phenomenon within the human dynamic, have a very important function within that dynamic. We are no random occurrence. If we appear, on the surface, to be a random occurrence, that perception only speaks to the limitation of our capacity to understand natural forces that govern the delicate balance of life on this planet, just as those forces keep the planets perfectly balanced in their dance around the sun.