And the result is: it is the judgement that those laws are referring to the biological sex (which it itself is recognised as being subject to some debate, too, so the judgement refers to another common definition).
That's all. It is not a redefinition or anything. I cannot really understand the enthusiasm of one side or another. It just clarifies what those laws were meant to say, and I tend to agree that anything else would most likely be an unintended reinterpretation. The judges also make it clear that if law makers want more protection for other groups, e.g., trans people, they probably need to make more laws for that.
I also find that this is a very complex topic, because it was about the question whether in sex separated prisons, it is more important to protect trans women from cis men, or to protect cis women from imposter trans women cis men. I mean -- who knows a trivial solution to that? The judges clarified basically that the original law was probably just concerned about protecting cis women from cis men, because probably no-body thought about it. And for the sake of clarifying anything, they said that "woman" probably meant "biological woman". They were tasked to decide something, so they did.
And, well, at least that's I read into this... You can have a look for yourself, maybe, before taking one side.
Segregate by sex first and foremost, and then within each prison estate further separate prisoners by risk categories. It's what's done already for vulnerable inmates: ex-cops, gang informants, pedophiles, etc.
The reason that some penal systems started transferring males to women's prisons wasn't to protect them from other males - this was a justification invented afterwards - but because they decided to implement ideological beliefs that promoted gender identity over sex. Regardless of how much risk this exposes female prisoners to.
Thankfully this sort of policy is starting to be reversed, or has been already, almost everywhere it's been imposed.
My understanding, reading the various reactions in the article, is that now it is fully legally safe to deny trans women access to the "women changing room", or to "womens" categories in sport, or to lesbian meeting places, etc.
Not really though, at least not for biologists, who have an understanding of sex that encompasses all sexually reproducing species, based on there being two gamete types of different sizes.
This is why it's described as a binary, because of the two distinct types of reproductive cell. By convention the larger type is the female gamete and the smaller type is the male.
Having these consistent definitions is how biologists can discover new sexually reproducing species and understand the specifics, like are individuals hermaphroditic (each individual produces or can produce both female and male gametes) or gonochoric (individuals with distinct and unchanging sexes), and if the latter, which are the females and which are the males.
Have you got any credible sources which support this statement? I have only seen papers which confirm that sex is binary and immutable.
Biological sex is not binary. There are (at least) three criteria to be considered:
(1) cromosomes. females are XX, males are XY. But other combinations exist: XXY, XXX, XXXY, etc. There is no universal agreement of how those combinations should be best matched to the binary system.
(2) phenotype. females have a vulva, a vagina, and ovaries, males have a scrotum, a penis, and testicles. But some people have no, or half, or a large, or small of one or another. Furthermore, the phenotype might not match with the chromosomes: one example is an XY chromosome type while the person has a vulva, vagina, and internal testicles. There is no universal agreement of how those people should best be classified to the binary system -- the best is probably to recognise that they are non-binary.
(3) hormone level. females have a typical level of hormons and males have different levels. But this is not universally clear-cut. This is one of the most frequent reasons for dispute at sport events when otherwise very obvious women have hormone levels that are 'too male'. Again, no universal agreement of what to do here: ignore the hormone levels in these cases? But why? Usually, they match. But not always.
There are also male outliers that have hormone levels that are higher than for males. These males might also be excluded from sports competitions for the same reason, despite being on the right side of the binary scale, but they are too far on that side. Again -- there is no agreement whether this is still the normal male category or maybe non-binary.
And this is just the biological sex. For gender and identification, there is more. If it wasn't so serious, it would be funny how some governments define sex as binary by reducing it to biological sex or maybe assigned sex -- it is really like making a law that pi is 3.
But note that the judges here made it clear that it is not their place to make a judgement on this complex topics.
More specifically: not all species have an XY chromosome sex-determination system (see ZW or temperature-based systems), not all species have the same anatomy for sexual reproduction (consider egg-laying species), and other species have different sex hormones (for example insects have a hormonal system unique from mammals).
The biologist perspective of sex is to consider gametes (sex cells) as the basis. Two types, with one type (female) larger than the other (male). All other understanding relevant to the exact mechanism in each species is built upon this.
So the court did just that, and defined (for the purposes of legislation) what "Man" and "Woman" refers to, i.e. sex not gender. A person with XY chromosomes, but some sort of developmental disorder that makes them appear feminine isn't some kind of massive puzzle from a biological point of view either, you'd just say "Male with AIS" for example. From a legal (in the UK now) point of view you'd say the same, and from a social point of view you'd say whatever that person identifies as.
People love pointing out that biology is complex, but for some reason bristle at the prospect of language that accurately expresses that complexity. And to be clear, if someone who is XY identifies as a woman... *Call them a woman!* It's rude and cruel to do otherwise, but from a legal standpoint it's unhelpful to play word games.
Yes, this is what the judges were tasked to clarify. And they clarified. The situation is better now, i.e., those laws are not ambiguous anymore (well, except for that 'what is biological sex' discussion...). It is quite an arbitrary clarification, but they clarified, and arguably, they could only do it wrong. They write themselves that they are not trying to define what sex or gender is. But they disambiguated existing laws, which by itself, is a good thing.
Obviously, this is not a good judgement for trans people, but the underlying problem is not with this judgement, but that the laws are not good. No definition of what sex or gender is will make those laws better. Judges cannot change that; legislation needs to change that. The judgement clarifies that the laws were made to protect cis women from cis men. The laws unfortunely do not protect trans women. And that's bad. Completely agreed.
The discussion here has drifted in the direction of how to or not to define biological sex -- and that's also not helpful for trans rights. But the topic is still interesting and no-one claimed to be solving problems, I think.
What the Supreme Court clarified the law doesn't do is grant them additional privileges, like access to spaces designated solely for the opposite sex.
When it comes to the law though, word games are unhelpful and get in the way, clear definitions are required. In terms of respecting human dignity, these definitions change nothing; people inclined to respect trans people will still feel the same way, and bigots will hardly change either. You can still have laws and legal structures designed to protect people while recognizing the reality of their biology, because it's about GENDER identity, not BIOLOGICAL identity.
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?
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.