The principle of anti discrimination laws is that ppl shld not be treated differently because of a protected characteristic

Exceptions are put into the law in recognition that sometimes fair treatment means different. Eg to meet needs related to disability, pregnancy, sex etc

This relies on an objective reason (usually related to something physical) or may be to overcome disadvantage of a group

Exceptions are also put in in recognition of freedom of association and belief. People should not be discriminated because of religion, sex, ethnic origin etc.. but people should be able to chose form associations based on characteristics & practice their beliefs

These two types of exception are different - the first is because of objective justification to exclude others from a public or commercial benefit, while the second is because of a freedom in our personal lives

There are some characteristics where there are significant needs for differential treatment - age, sex, disability, pregnancy, and others where there are not - eg sexual orientation and race

"gender" has often been used as a synonym for "sex".

Its not clear what it means, but recently often read as "gender identity"

Like race and sexual orientation there is no objective justification for treating someone differently because of gender identity - eg. A rugby club should not treat someone differently or worse because they are gay, black, jewish, or identify as non-binary

But there are lots of situations where #sexmatters: you can and should treat people differently because of sex - in hospitals, changing rooms, sports, toilets etc...

The conflation of "sex " and "gender identity" is confusing and makes sex based rules difficult to explain and enforce.

If we say sex when we mean sex things become simpler and clearer .

The words man, woman, male and female relate to the protected characteristic of sex.

"gender reassignment" when it was first conceived of was a physical type of characteristic -- a person was embarking on a process of physical changes to their body which might therefore require the first type of exception to discrimination rules - to meet an objective need.

But right from the start there was wiggle room, and this has been expanded and expanded. Today the majority of people covered by protected characteristic have no physical changes to their body, or have only facial or breast surgery. Nor is a diagnosis required.

A PC that does not relate to any physical or objective difference, is more like race or sexual orientation -- something that should generally be ignored by employers, service providers to treat ppl equally, rather than something covered by specific needs like age & sex

It operates more like a belief -- some people believe in God, some don't . Some people believe in gender identity some don't.

People should not be harrassed or discriminated for either set of belief, and orgs should check that rules and policies don't indirectly discriminate

But none of this needs to undermine the operation of the protection against sex discrimination (including through the provision of single sex services where justified)

Because sex is a different protected characteristic, and a wholely different thing.