@Tandora
Treating them according to their experience of sex, and not what we are able to externally "observe"/deduce about their sex based on observation at birth.
Very happy to treat them according to their "experience of sex".
And ti that end, it is important to realise that a trans women's "experience of sex" is fundamentally different to mine, so much so that the two are entirely unrelated. I have no more in common with a trans women's experience of sex than I do with what you would call a cis man.
My "experience of sex" is simply the lived experience of being of the boring simplistic type of female. The capabilities of the body, growing to self awareness within the historic and cultural constructions around that body and how they intersect with my self knowledge and others' reactions to and expectations of me. It is entirely predicated not
on some sort of a priori knowledge of being "a woman" but the opposite, a blank slate forming into consciousness within the fact of the body.
So given that, will you acknowledge that my experience of my own sex is nothing to do with whatever trans women experience, my experience of sex is also valid?
To take the analogy of "Hunger", I cannot know if you and I experience hunger the same way. Perhaps the physical feeling of Hunger for you is like the physical feeling of Itch to me.
However what we can see is that your Hunger and my Hunger have the same consequences. Food relieves it, no food increases it, if it is ignored or unsatied for too long, there is death of a specific type that can be measured and identified as starvation even though I am no longer around to tell the tale.
And we can therefore say that my Hunger and your Hunger are the same thing, and are different to Thirst, not because we know the subjective experiences are the same but because the outcomes and consequences are.
And this is how I know that a TW's experience of sex is not meaningfully related to what I experience. Not because I know how he feels, but because the outcomes and consequences are so different.