It is impossible to separate sex and gender under cisnormativity

So long as society extrapolates gendered ideas about one's skills, desires, roles, ideal partners and body based upon birth assignment, phenotype or presentation, and conflates them all, there's no way to invoke one without the rest creeping in.

If you call an anatomical configuration "male" or "female" you've already invoked gender.

And unfortunately, if we sat down and worked out different terms for these reproductive configurations, society's need under cisnormativity to associate one set with men and one set with women, would mean the new terms'd be entirely gendered in less than a year of widespread use.

Relatedly:

While doing away with assigning sex on birth certificates is essential to weaken cisnormativity, it wouldn't by itself do away with birth assignment. There's no way to do away with birth assignment altogether under cisnormativity.

A child who has no sex assigned on their birth certificate, under cisnormativity would still be put into a gendered category at doctors' offices, would still live in a society that said "penis = man, vulva = woman". They'd still grapple with Implicit Assignment

Nothing about this is me defending this state of affairs. Cisnormativity is an oppressive hierarchy, and its violence can't be overstated.

I just mean that society has hard-coded any talk of anatomy as automatically gendered, and it fucking sucks.

This also isn't me saying there's no way for trans people to be their genders. I'm saying the opposite. I'm saying cis people can't be trusted to use the term "sex" in an nongendered way, so don't grant them the term. Take all the terms.

A lot of us experience sex and gender as different. I certainly do. I struggle to put into words the way they differ for me. But neither my sex nor my gender are contingent upon the genitals I had at birth, nor whether my repro system developed from Wolffian or Mullerian ducts.