Asklemmy

Male and female are useful in biology, and therefore in medicine.

As I explained in another comment, in human medicine it is much less useful than knowing what parts a human has and what lab results can tell us about the relevant hormones and other biomarkers of interest. Most people interact with medicine on a personal level, and because of such having more detailed conversations with your doctor(s) will often result in better care.

With that being said, used as a broad term to describe broad effects such as when classifying data at the population level, it can be a useful and quick piece of information to collect. If you're trying to determine compliance with social determinants of health, it may be faster to collect sex (or gender) than it is to ask people to create a catalog of the important body parts or to ask other broad questions such as "are you disabled" to understand systems better.

It's an interesting concept, to have a term which is most useful at a certain level of abstraction and less useful the less people you're referring to with it. We've got a decent amount of these in our lexicons and yet I see people drawing false inferences all the time. It's almost as in if we aren't having conversations about how broad terms like race, gender, employment status, etc. can be useful when dealing with population level statistics for the purpose of understanding systems, but not particularly useful on an individual basis when trying to determine information about a individual or a small group of them.