This is taken from an article and better describes what I was thinking about than I would be able to convey.
Of course teleportation isn't probable for a very long time if ever, so this is purely hypothetical. Then again they have already succeeded with it at an atomic level...Suppose there existed a 'teleporting' machine that worked by scanning your body and creating an exact duplicate of you, atom by atom. Assume that the replica would have the same personality and memories that you have (that is, don't consider the possibility of your selfhood residing in an immaterial soul) and that the procedure is instantaneous, so from the point of view of the replica it has just been teleported, having a continuous experience from being at one place to being at another. Then, is there any reason to consider 'you' to be the version of you that remains at the same place, instead of the replica? If the machine works by killing the original 'you' at the same time that creating the replica, is stepping in the machine a form of suicide or just a convenient way of transportation?