We all know the recommendations around collecting a user's gender or sex, especially as a single binary field: don't. There are so many brilliant flowcharts and diagrams and essays publically available that all remind us that it's none of our business.
But... what happens when knowing someone's sex IS your business? for example, for a doctor's office?
Clearly a male-female radio button isn't going to cut it. But what would? and what do doctors actually need to know about a patient's sex or gender? Spoiler: the answer is not what you might assume it would be.