

but what about ovotesticular people? if they can produce both gametes what determines their sex? based on what gamete they were “supposed” to produce? but how do you determine what they’re “supposed” to produce? chromosomes? phenotypes? a combination of all of these? but then we’re back at square one where gametes may be binary but sex isn’t?

but even then people who can’t produce either can’t be simply classified into what they were “supposed” to produce without involving karyotypes or other sex characteristics, which the paper you linked explicitly argues can’t be used for sex definition:
so for someone with complete gonadal dysgenesis:
but then this is circular:
and I feel your lacking-an-arm comment doesn’t really apply here as humans aren’t solely defined by how many arms we have - the analogy would only work if:
but I think the bigger question this whole biological definition/determinism sidesteps is the one that seems close to heart of the very-same intersex people linked in that Wikipedia page:
when these things affect human beings we can’t try to wash our hands by clinging to models that seem to give us simple answers - if we insist on monothethic definitions that don’t recognize the complexity of sexual development - we end up forcing ambiguous cases into boxes and providing intellectual cover to deny people agency over their own bodies.