One could imagine just putting a text entry field for gender, so as to not other any gender identity that doesn't align with the male-female binary. One could also imagine putting other fields in for respondents to self-identify as trans, should they want.
That said, it seems a very neutral approach to gender self-reporting is self-defeating (consider that, at least for bathroom laws in some US states), the very notion of something that's not on the assigned-at-birth male-female binary is itself controversial. I guess if your gender choices included "deconstruct the male-female binary" or something, that'd be overtly political, but at least in this political climate just acknowledging the existence of some people seems to be a political act. (one I'm in favor of, fwiw, but I'm one of those people that argue that being "apolitical" is just cover for being politically in favor of the status quo).
