Should the UK have a simple, clear legal definition of sex, male and female?

No. You are making an error in thinking that if sex were defined in detail it would be defined as per your specifications. The last thing we need is to open up the idea that sex is something insufficiency well understood it needs a new definition of any sort.
We know what it means. If people want to argue it means something different the onus is on them to prove their case.

If you’re asking whether there should be a statutory definition (which we don’t have) vs a legal definition, what your opening post asks about - which we already do have, then no.

We have had a Dangerous Dogs Act since 1991. If decades later we legally classify certain cats as dogs then it radically and retroactively changes the perceived intentions of Parliament when in 1991 it passed that law. And there is no way that politicians will be able to avoid changing the legal meaning sex as it stands.

I think there should be a law to make it an offence to lie about your biological sex if asked to disclose it by any authorised person and to lie about your biological sex to anyone if asked to disclose it if providing or receiving any intimate service.

The devil would obviously be in the detail.

DBS needs sorting too.

I agree with PPs that we already have a definition of sex, from Corbett v Corbett.

It's what's on your original birth certificate. Case law such as W v W has given us robust guidance on what retroactive changes the Registrar can make in case of a DSD.

It would be useful to confirm that every reference to sex in law means this. I believe this will follow logically from R on app. GLP et al v EHRC, where Swift J elegantly demonstrated that a sex-relevant instrument that lies outwith EA2010 by virtue of Schedule 22 must have the same meaning for sex as EA2010 does.

ID needs sorting.

I think the UK should have one and now it does with the Supreme Court Ruling.

In each instance where people want rights outside of that, for example the man who says he is a woman and not getting a job because that role will involve the rights of women to same sex treatment not being met, then that is clearly a good reason to not get that job. We need to go back to the original reasons why single sex treatment or spaces and if there is good reason, that reason needs to stand.

For NAL nice analysis.

Everyone knows what the words means.

Tthe illegality of the trans movement alleged to change terms. But did not.

Any legislative change would be dangerous. It opens the door to the unknown.

Also you’ve ignored NI, how EU sits and how any significant change can be challenged.

We know what’s what, people will get in line.

The trans delusion will wane.

You’ll be left with the odd old man prancing around in a skirt.

There will be a wave of now teens suing in next 10 years when they realise drugs have rendered them asexual or surgery has rendered them infertile.

I think that passing a new law with an explicit definition of sex is unnecessary. The case law seems to be adequate, now that we have the SC judgement. And any remaining legal pushing and shoving around the issue just reflects a real set of social tensions. It isn't the business of Parliament to erase social division by pre-empting any remaining skirmishes in court.

It also isn't the business of Parliament to state material reality as extensively as suggested in the OP. That would seem authoritarian, and might even place some legitimate researchers in the same situation that Galileo found himself in. After all, scientific definitions are meant to be open to testing and revision. As obviously true as the components of the OP's definition are, it isn't right to take them away from science and give them to the law.

I think that in the US there have been some instances of legal overreach, such as defining sex and creating criminal offences relating to wrong toilet use? When unnecessary laws like this are passed, it seems ideological and persecutory. It would create some basis in truth for the TRA claims of being victimised.

I think the Supreme Court judgment settles the matter. As it should have been years ago, which would have saved a lot of heartache.

But you have males claiming to be female. Are you saying they are just batshit and deluded?

They are not arguing in good faith. Playing chess with pigeons springs to mind.

I agree with @MyAmpleSheep we already have law. And it’s good and makes sense. The problem is that some individuals dont accept that, and that will still be the case regardless.

For some folks, there’ll never be a shared definition unless it includes men. And for the rest, the definition is pretty clear.

But it is defined. In law. It was defined in Corbett v Corbett. It has been defined in law since 1970.

It's only argued about by people who are ignorant of the fact that it has already been defined. That's a problem of ignorance, nothing else.

Do I think the definition needs to be more widely known, especially by those people who think it hasn't been defined? Definitely. Does it need defining? No. It's already defined, and it's a very good definition.

The people that keep arguing are those that just refuse to accept any definition that separates males from females, no matter how you define them.

@SingleSexSpacesInSchoolshow??

How is this still being discussed?
There’s male and female. That is it.