I haven't had this experience myself. So I can't comment on it directly. But I do think good therapists pay attention, and notice, things we perhaps aren't even aware of. I recall one session I had with a gender therapist. I don't recall what we were discussing in particular. But, during the discussion, she said: "Well, you know you don't have the most masculine walk." This was something I was totally unaware of and certainly hadn't been doing consciously. But it was something she noticed. Perhaps those of us with gender identity issues reveal our true selves in subtle ways the average person might not pick up on but that skilled therapists do.