I want to add in an apology to you, AlwaysChanging, as I used transgendered alters as an example of poor reality testing, when it is actually becoming clearer and clearer through research that transgenderism (as a stand alone and not specifically related to DID) is a very real and natural way of being caused by genetic and biological factors. (And, of course, can exist with and alongside DID to complicate matters even further!)
Sorry - I just wanted to clarify to avoid you possibly feeling invalidated by me using transgendered alters as examples of 'impaired reality testing'