I was flying last week from Seattle airport, wearing women's jeggings, a long hoodie, sneakers and very light make up. I wasn't trying to pass (not even close), but at the security check, the TSA agent asked me (I think) if I was presenting as a man or a woman. I was really surprised by the binary question, so I answered "neither, I'm in between". He then repeated the question looking at his female colleague, and then I simply answered "Male" and that he could search me (I think the scanner detected my padded bra).
He remained very professional, but I'm wondering why I had to make such a binary choice? Why can't I be 'something else'