Many transsexual people I have encountered over time have chosen to introduce themselves to friends or acquaintances as being more than "just" transsexuals.
Instead of just being honest about having been biologically male or female, and having changed that, they invent stories about having been born intersex - presumably because in their minds, the audience will somehow view them more sympathetically that way than if they were just honest to begin with.
Why can't they just be honest?
Well, as it turns out, there may be some very good reasons why they do this.