"the most infamous example of cis people failing to understand the way they themselves think is in the realm of what constitutes sex. If you ask a cis person to define what “biological” sex is, nine times out of ten they’ll cite genitalia or chromosomes."
but trans* experience tells us that both gender and sex are socially constructed and performative. While gender is signified by clothing, body shape, hair and other overt appearances, sex is signified by the look of your face and skin (another intersection of cis and white privilege intersecting to construct the ‘normal body’), the sound of your voice and other really subtle signifiers. If your performed sex and gender don’t match, thats when you get read as trans. It has nothing to do with genitals or chromosones. (well, except that chromosomes may partially determine our bone structure)
Even amongst ‘rad-queer communities’ I am always read as ‘male bodied’ … even though no-one has ever bothered to ask what bits I have. I also have never had a chromosome test done, how many of you have? so how do you know your ‘sex’ then? So how am I ‘male bodied’ then? My face, my jaw, my voice are what constitute my male-ness (but not my masculinity), in my case also my height.