you said "if you’re going to determine sex by the gametes an individual has at any time had, then those individuals must actually have had gametes at some point, or else they’d be classified as sexless"

that would be the equivalent of determining a female breast from lactation. it is not the lactation that makes the female breast female, and it is not the capacity for lactation (which can be affected by medical conditions) that determines the female breast to be female. we can tell the female breast is female, not by the lactation itself, but because it follows a design for lactation regadless of if there is a deformity that prevents lactation and regardless of it she never has a pregnancy and never lactates.

whether or not the gonads properly form/differentiate in the mesoderm does not change the fact that the sperm cell carries either an x or a y chromosome. can't remember exactly, but you mentioned something like not rmemebering middle school bio or not remembering freshman bio. i feel like having a better understanding of how reproduction works, in humans, in plants, in worms, in hermpahroditic animals, in bacteria, in the full range of organisms, will help you to better understand how it's not nearly as ambgious as you're making it out to be.

the zygote is male or female BEFORE the gonads form.

seeing as how we aren't discussing intersex conditions, maybe this will help it makes sense

a male is created when a sperm has a y chromosome (resulting in a male xy individual) and a female is created when the sperm has an x chromosome, (resulting in a much more genetically vigorous xx female).

it is not the production of the gametes itself that makes someone male or female, but the fact that they are in the category of people, who, if things develop without mutation of deformation, are engineered to develop those gametes.

all cases of interesex still fall within the binary but can not be determined on sight (hence the ambiguity) but CAN be determined with genetic testing.

basically, by your line of thinking, the fact that people with down syndrome face didn't develop a normal face someohow excludes them from the category of human because humans are supposed to have normal face. and then you're like "well, this kid with down syndrome doesn't even look human, how can i be sure they're not really a dog or a mongoose?" but, even if you don't see an obviously human face on the down syndrome person, genetic testing will make it clear that the person with down syndrome face is really a human too, despite the fact that it may not be aparently obvious to everyone. some people will think it's obvious that's a human while other people may be a little on the fence. but if you look at the genetics it will be very clear that this isn't a non-human, it is simply a human gone awry.

the same can be said about sex. just cos someone comes out with their junk strange or their biologies acting in a pathological way, whatever disoder or disease doesn't somehow take them out of their sex any more than down syndrome face takes someone out of being human.

there ARE intersex conditions where, despite the chromonsomal sex being xy they are functionally socially female as far as we are concerned on a social level. but slotting them into a gender when our society demands it does not change their sex. the idea that a male who develpoped as a female was raised as a female and that since gender is nothing but bullshit and socialization their gender identity therefore reflects the socialization of having an aparently female body. nothing about "we mistook these males for female, and also, even if we had known, they still would have been aparently female to all observers and therefore gendered as female" suggests permeable boundraies regarding sex.

intersex males raised as females DOES tell us that gender is bullshit and just an imposition on humans. it is a good argument for "well, why should my behaviors or mannerisms or gender expression be restricted in any way by my sex since we have clear evidence that gender is nothing but a social navigation and while there are def biological factors that impact your gender, the driving factor is not sex. xy males treated as females shows us that the social aspects of gender are not sex based, and, whatever brain development/hormones issues might play a role in gender, we can definitivly say "because your your sex, you must gender in accordance thusly" is a load of crap (meant to extract free labor from the lower classes and the female body)

none of the gender issues with intersex point to any confusion in sex however, simply gender. the diversity of intersex people and how itersex impacts a person's gender can tell us a lot about gender (basically that it's bullshit and socialization). but intersex people don't tell us jack shit that implies "we can not determine someone's sex." we easily recognize intersex people's sex in the lab. intersex people are a great argument for "your sex shouldn't have any bearing on the gendered ways you express yourself," but it is a terrible argument for "we just can't tell who's male sex and who's female sex" because the simple existence of intersex and our ability to determine their sex despite it being aparently ambiguous and despite it not aligning with gender tells us that sex is very very very very fucking easy to observe and not at all confusing.

you didn't bring up intersex people, but getting into chromosomes and gametes make me feel like i should point at that intersex people are proof that there ARE two sexes and that no matter what kind of ambiguity, that the ambiguity is surface level and that when you look beyond the surface the distinction between the male and female sex is as clear as night and day.

intersex males are male and intersex females are female. there is no middle ground. that some of them live opposite sex social roles in an argument for transgender, but it isn't an argument that sex is in humans ambiguous.

there are people who literally are born without assholes. we know they are "supposed" to have assholes from looking at all the humans and seeing where they went wrong in not developing an asshole (seriously, make sure your baby has an asshole before you take him home, because sometimes it's missed and then the baby dies). You wouldn't say "oh, i guess some humans don't have assholes" anymore than you would say "well, i guess some people of the female sex yeet."

a female or male who has a mutation or development problem to appear the opposite sex doesn't take them out of their sex category. a female who is so virilizaed that's she's got a beard and is hulking over everyone and that everyone assumed her 3 inch clit was a penis, and then she didn't menstruate because of test and lives her whole life thinking she's a man is still a female. a male who develops a tiny vagina and tits and doesn't have a dick is still a male.

i'm a ftm, and also am super virialized to the point of being mistaken for a man with no attempts at passing, being bigger than a man, having a man "personality" (which i admit is probably an interplay between genetics and socialization and not simply genetic) and displaying the index ring finger ratio of a ball buster. to me there's a huge difference between someone reading my gender and putting me in the "man" category (very affirming) and someone deciding that because my female body is masculinized that therefore it is a male body.

pre pubtery when i thought i was intersex, "you're tall, you're probably a boy" would come across as othering and telling me how i'm supposed to be. but even in the context of gender bullying, there would have been no offense taken because we know from mahoney that little boys can be seeming like little girls.

despite a very firmly rooted male gender idenitiy (i had this whole backstory where i assumed i was an intersex boy who'd been mutilated up until menstration started), when you get into the part where you're describing (non transitioned) masculine people of the female sex as if somehow their sex is ambitious, at that point you're insulting them on their biology. you want to tell me i'm a boy because of all the boy ways i be like, that's fine. i feel my gender is recognized. but when you start saying that what makes a female male is that she's man sized or that she's got a beard or that her clit is indistinguisbale from a penis, at that point i'm like, wait, you're not affirming my gender. you're just throwing freakishly mannish feamles who you don't know shit about their gender, under the bus. it's actually very insulting to masculine females to suggest that because they are masculinzized that that removes them from the caterogry of female.

edit: people with down syndrome face are discrimated to the point where people will try to stop a down syndrome marriage. legit, just slow people having a regular normal life, not talking about someone being preyed on, but 2 legit down sydrome people trying to be happy togther, will have normal people try to step in and control their life.

i do think there are biolgoical aspects that affect gendered behaior seperate from socialiaztion, but they are not neatly divided by sex. like i said about finger ratio, if you look at the finger ratio of someone like hiliary and see her acting like a dude, i do think there may be some genetic aspect of her being assetive and agressive, but since she's obviously female it's obvious that it's not sex that's controling that. likely some things we associate with sex, like homrone levels, which are shown to affect the digit ratio. a viralized female is still female tho