Scientists tend to understand that part, that's more of a political/cultural thing (I'm ignoring the language part here entirely about which terms to use for which concepts here).

There's the X and Y chromosomes, those produce a binary result (unless you have a genetic anomaly). And after that comes the messy and fuzzy parts I mentioned, where those genes trigger changes in hormone levels and development. And those parts are analog, very complex and contain a lot of different parts. So the outcome is not binary anymore.