Thank you for actually engaging. Too many people on Lemmy are worryingly anti-scientific due to their politics. To anyone that needs to hear it, join us on the science-accepting Left. Life’s easier without cognitive dissonance :)

To clarify, the fact of the sex binary doesn’t have any strong implications for surgically altering intersex children. People simply don’t understand that the sex binary is a limited, but factual claim. There’s several different domains here, and people keep confusing them and then arguing with me. The fact of the sex binary doesn’t mean that sex phenotypes or genotypes aren’t a spectrum, nor that gender roles need to be tied to sex. It also doesn’t mean that someone with a DSD needs “fixing”, particularly surgically before they can reasonably consent. It is possible that interventions are the appropriate course of action, but not just because someone is “supposed” to be a certain way.

Even in the case of complete gonadal dysgenesis, a person’s body is still “trying” to produce gametes, it’s just failing. My arm example is still relevant. It’s not about the number of arms, it’s about what’s missing. No person is born with a body that’s “trying” to produce a fish instead of a hand. Nobody was born with a body that’s “trying” to produce nothing instead of a hand. In both the case of a missing hand or gonads, the body was “trying” to do something and failed. Evolution is flexible, and it’s possible that someday, a new body plan would emerge that does lack a concept of hands or gonads or whatever, but that’s not the reality today.

Note that “trying” is a bit too anthropomorphic and loose of a term, but it’s good enough. It doesn’t imply that there’s a deity or sin or anything like that, it’s a description of a natural process, like gravity.

So experts can look at the correlates and determine the likely sex based on the apparent body plan. It’s not just karyotypes, they can also look at nearby structures like Müllerian/Wolffian ducts. The important thing to remember though is that experts can be wrong, but that doesn’t change reality. If an expert said “this person’s sex is male”, then gave that person a magic science pill that fixed whatever developmental issue they had, and they started producing ova, that says nothing about the sex binary. It merely means the expert was wrong and the person’s sex was female the whole time.

So when you say “if sex is defined by gamete function”, you’re missing the crucial “biological function” bit (a.k.a. “organized around” as I’ve been using). Here’s the corrected version:

• sex is defined by the type of gamete one has the biological function to produce
• in non-gamete-producing cases, experts would look at determination mechanisms to figure out the likely sex
• those experts might be wrong
• the sex binary remains unperturbed regardless of human hubris