The law has said all sorts. It doesn't change material reality. Good that you are acknowledging the supreme court decision though: a GRC offers you no extra rights over those of other men.
The law had indeed said many things, and things change over time. However the text of the EqA has not changed materially, and the intent of parliament was expressed.
One judgment of any court does not change statute without itself legislating from the bench.
The arguments made by the SC make no sense in English in plain language, let alone on the level of statutory construction.
I can quite understand that they look elsewhere in the EqA when trans are not specifically included under the grounds of sex, which I'll grant anyone would seem the obvious place.
However thinking that it could not be found under pregnancy and maternity points to the same absurdity that you identify - nobody has reproductive potential but cis women and trans men. But trans men are not identified there either, meaning only that this was not a gateway expression of sex.
However again, parliament did express their intent under the grounds of gender reassignment, which does say that sex is reassigned under this provision ...
Under Section 7 of the
Equality Act 2010, a person has the protected characteristic of gender reassignment if they are proposing to undergo, are undergoing, or have undergone
a process (or part of a process) to reassign their sex by changing physiological or other attributes. Protection does not require medical intervention, a Gender Recognition Certificate, or a permanent, irreversible change, as it applies to individuals in any stage of transition.
This asserts the deeming provision of the GRA ... ''for all purposes'' etc.
I will assert that this final sentence is the explanation of why the construction of the EqA places the definition here in Section 7 ...
Protection does not require medical intervention, a Gender Recognition Certificate, or a permanent, irreversible change, as it applies to individuals in any stage of transition.
Therefore the legal standing of the individual is defined here. This is the gateway test for standing in plain English, and standing is without or without satifaction of the deeming provision of the GRA.
My argument is entirely neutral, it is not any form of advocacy of any special treatments. I'm not required to agree or disagree with it. It is a matter of neutral fact ... anybody in the process of reassigning their sex is covered.
As James Bellringer points out - the term ''gender reassignment'' becomes a nonsense phrase especially as a legal protection, since it is not gender that is asserted as being reassigned by the provision, but sex. He is not alone, the then serving AG Vera Baird was herself critical of that term during committee stages before the Bill was put before parliament, which chose to retain it.
If sex is reassigned by definition, then the derived treatments must follow from that definition.
