Sex shouldn’t be offensive and has only been made so by the same kind of pressure under which people in the Victorian era swooned or were titillated upon seeing an ankle. It’s nonsense.
Only a few years back, those who had a severe hang-up, to the point where they were considered candidates for so called “medical sex change” we’re carefully counselled to ensure they fully understood the fact that they were the sex they were, and that any operation was cosmetic and to alleviate the distress they felt because of their sexed body.
Abandoning that common sense approach, where those distressed by reality were helped to accept it and acknowledge the limitations of treatment, for an approach that requires the entire population to lie in order to validate a false idea, is exactly where the problems began.
You can’t force the world to lie and any treatment that requires that is doomed to failure.
Sex should be requested, using the wording most likely to elicit the highest rate of truthful responses, while still maintaining reality in the description (ie assigned at birth doesn’t represent reality, whereas observed at is generally correct).
If “gender identity” is to be mentioned at all, it needs to be clear it’s a belief system. “Do you consider you have a separate gender identity from your sex” might work, but equally might be too confusing. “Do you consider yourself to be transgender” might be clearer. Either way, it can’t say “are you transgender” or “do you have a gender identity” as both those things are currently faith based descriptors.
Or it might be best simply to ask about gender reassignment, seeing as that has been reified in law, despite its abstraction, caused by the ludicrous suggestion that you can claim that you are covered, even though you haven’t done a thing to start the process.