So, in a nutshell, the assertion is that gender is entirely nurture and not nature.

Yeah, sorry, that is an extraordinary assertion and I’m going to need extraordinary proof.

Are there people for whom gender and sex don’t neatly match up, or even those for whom it is purely performative, sure.

But they are statistical outliers, and not representative of the majority experience.

People can be different then the statistical norm, and that’s ok, but to assert that this norm is entirely cultural is over the top self serving.