Does anyone mind if I go back to an earlier post which is more on-topic?
Agatha very concisely said - for what TWAW types believe the definition of woman is -
"Sure. They say things like: gender is the social meaning of sex, where that means it's the collection of traits, behaviours, preferences and personality types that are socially ascribed to people who have, or are perceived to have, a given body type. Being a woman is identifying with the gender that society ascribes to women (in the sex sense).
To be clear, I am what they would call a TERF - I think that sex, and sex based discrimination is what matters. But I am not baffled by their position, I don't think it's incoherent or deranged or so insane it's staggering that anyone could think it. I just think that they're wrong, and my interest in finding out exactly what they think and how they define things like 'women' comes from wanting to really point out where they go wrong (unless of course they change my mind before I change theirs...)"
So - essentially, femininy socially determined traits are inherently linked with being female, and masculine ones with being male.
The difference between a GC and a TRA sort of person is that a GC person believes that feminine and female can be mutually exclusive - being one doesn't mean you're the other - vs believing that the traits are linked to being female, and, broadly, can't be uncoupled.
So I can understand this in my grandad's generation, and even today, loads of people have 'traditional' views about sex and gender.
But so often, as in the OP, it's people who have clearly thought about this, have been conscious of avoiding gendered stereotypes for their kids, are aware of the specific issues that come with having a sexed body - that sex does matter in some situations, such as medically, in sports, in relationships - but still insist that having THOSE traits mean you are THAT sex, there's no getting away from it, that sex is who you truly are.
Often it's intelligent people who have thought about it - to a point. Then I think the thought-terminating cliches kick in.