There has to be a common sense and widely agreed definition of "woman" and "man’"or we’ll all disappear up our own fundaments – which very likely is the point of all this, i.e. keep us fiddling while the world burns.
The underlying, material reality is that, in nature – and we are natural beings however much some of us try to pretend otherwise and however hard others work to maintain that pretence – sex exists for reproduction. It does not exist purely for pleasure or fun, or as commodity, a marketing tool, a weapon or a competition.
Peel off all the social layers and the core of reproductive sex is unambiguously dimorphic – i.e., the creation of new life needs the coming together of functionally distinct female and male elements – of which the female is the far more important because of a long gestation of a, mainly single foetus, and the birth of utterly dependent and slow maturing offspring, the care of which has always fallen mostly to females.
This arrangement was and is not just because that suits males, but because in the subsistence societies that make up the vast bulk of our evolutionary and social history, human infants were utterly dependent for a long time on a lactating female – most commonly the biological mother.
Every human life that has ever existed came out of the body of a human who was functionally female. Despite the best efforts of trans humanists who would argue it is in women's interests to use technology to transcend that fact – to "free" women from their "reproductive burden" – it will always be that way given the same sort of people who want to create artificial wombs, clone humans from skin cells etc, are likely to destroy the world as we know it before such technologies can come to pass. That's aside from the host of ethical questions posed by such research.
Those who see trans humanism as the new frontier of human evolution also need to be aware that these super technologies only ever benefit the elite – the mass, as always, will be of no consequence.
Gender sits on the bedrock of, and draws its power from, the material realities of dimorphic reproductive sex and millennia of biologically determined and conditioned layers of functions and roles.
You can’t just turn all that off by an act of individual will or even by a collective making the declaration that the follow on act from the "end of history" is the "end of sex". Nor can you force a change in reality for all those who live outside the bubbles of relative privilege in which the gender performance artists mostly live.
Gender in this sense, is not fixed; it shape shifts to reflect societal needs (usually defined by the dominant social class) and it adversely affects women in varying ways and degrees, according to such factors as class, race and age – but the averaged effect on women is negative.
However, the ideology of gender also benefits men differentially; it cements averaged male power over females but, being part of the dominant sex is an illusory compensation handed down to otherwise absolutely or relatively powerless men.
To me, the common sense definition of female is the human being who is presumed at birth to have the potential to bear children, and who is presumed will go through the menarche, and the menopause.
Whether she is in fact able to, or chooses to have children, or if she no longer has the ability to have children, is beside the point. She will still carry her share of the weight of thousands of years and current forms and degrees of oppression and exploitation within various sorts of phallocracies.
The current trans orthodoxy (which does NOT reflect the views of all trans people) with its dogma, its catechism, and its tactic of branding, demonising and ritually insulting anyone who dissents from it, is actually phallocentric.
It is why over the past five years or so, male-bodied people claiming to be trans women have popped up all over the internet abusing and threatening dissenters – especially lesbians – with phallocentric insults like, "suck my lady dick’"
If you think saying this makes me a TERF, transphobe, transmisogynist, bigot, literal killer of trans people – then I respectfully suggest that YOU have a problem, because I am none of those things and frankly, I will match my socialism and feminism against all comers.
I have followed this debate for years – not just dipped my toes into it recently and I smell the presence of all sorts of political rats and spin-doctored dead cats – as do a lot of other rational, reasonable and progressive people.