Chatgpt is wrong here, sex is more like a series of bimodal bell curves measuring traits like gonad type, chromosomes, hormone levels, secondary sex characteristics, neurobiology, and probably some more I'm forgetting. For each trait, one bimodal peak can be labeled something like "typically male" and the other "typically female". For instance, hormones would have "higher testosterone" for one peak and "higher estrogen" for the other. You can usually categorize male vs female by weighing where an animal falls on these bell curves across all traits, but that's more of an art than a science, since the scientific perspective is more "sex is a composite profile" than "sex is a binary to be categorized".

That's why you always hear people say 'it's a spectrum" or "it's socially constructed", because that's the easiest way to explain it in simple terms (even if it is non-descriptive and annoying to hear as a shibboleth)