[dustedcodes]

Ok what you both say makes sense but none of what you said so far negates the fact that strictly speaking sex is binary, defined by the existence of a Y chromosome and that this is also immutable. It’s completely possible that the externalities presented at birth may lead to a wrong sex assignment, but that is a separate issue of human error isn’t it?

[beeforpork]

No.

Why is it so important to you that sex/gender is binary? Maybe try to relax and be a little less judgemental. It really does not matter for you what other people's sex is.

Intuitively, for normal people on the street, and arguably for politicians trying to define that sex is binary, how you would read a person is their sex. So that is, I would say, the historic traditional way of determining sex: by look and intuition (called common sense, usually). That's also how sex is determined at birth. (Note that in some cases, nurses need help with that, because it's not intuitively clear...)

Because this intuitional method does not work well, other ways have been tried to find something more objective than having a quick look. We found the sex chromosomes. But they are not binary either, as mentioned above. Now, one way of making chromosomes forcibly binary is to take the check for a Y cromosome, as you say. But that's just one arbitrary simplification. It is not an universally agreed criterion, because it does not always match with other criteria, particularly looks/intuition nor hormones.

And even intuitively, I argue, you should know that sex is non-binary. There are people where you cannot easily read the sex. You have an immediate intuition most of the time, sure, but not always. And then, as mentioned, your intuition may contradict chromosomes and/or hormone level categorisation of that person.

Another example: typically, an XY chromosome person with female external genitals is most probably read as clearly female. But by chromosome judgement, as you suggest, they would be clearly XY male. And at birth, they are most probably be classified as female. But they do have testicals and high testosterone levels, which again is totally in line with the male chromosomes.

Sex is not binary. Really. The world is not that simple. I'd argue that instead of trying to force sex to be binary, we should just try to not care so much about sex and gender. Because why?

[fzzzy]

So you are saying that someone with complete androgen insensitivity syndrome should use the men's bathroom, even though they have fully female genetalia?

[dustedcodes]

Huh? Nobody made any statements about bathroom usage or such, nor has the UK ruling anything to do with bathroom access. We are discussing the definition of sex and how the court ruling came to the conclusion .

[fzzzy]

You are arguing the presence of a Y chromosome is what should determine whether someone's passport says "Male" or not, right?

[EA-3167]

To be clear, that's not what this ruling says, that would be a consequence of other laws that can be changed if there's political will. The ruling is just a narrow definition for legal purposes of what the words "Man" and "Woman" mean. If a law is passed allowing for gender identity to be on a passport, then you could have someone who was afab put "Male" on the passport if they're trans.

And if such a law isn't passed, or a law explicitly banning that is passed, then *that law* is the issue, not the definition of sex dictated by biology. Remember, sex and gender are not the same.