Lawyer W. Burlette Carter, who has been following this case closely and filed two amicus briefs on it, has an excellent thread on the ruling here:
twitter.com/wddaughter/status/1272553010917507075
She thinks it is a good outcome that protects the employment rights of gay and trans-identified people without redefining sex. She mentions that in one of her briefs:
I asked the court to rely upon a decision, the Oncale case, to find that discrimination based on the presentation of Gender is banned under Title VII without overturning distinctions between biological sex and gender identity.
And on a straightforward reading of the majority opinion (by Justice Gorsuch), the court seems to have ruled along those lines in the case of Stephens, i.e., that Stephens was fired for presenting in a feminine manner, when a female employee wouldn't have been, hence, discrimination on the basis of sex.
The worry, for me, is the slippery nature of the concept of 'gender identity'; most crucially, the way it colonises the language of sex and thus transforms it. Since 'gender identity' uses the language of sex to conceptualise itself, merely referring to it is enough to subtly shift the meaning of sex from a physical locus to a psychological state.
We can see this in the way the Gorsuch refers to Stephens' 'sex identified at birth' - the last three, unnecessary words are almost certainly entirely new language for the court (I bet every other case involving sex discrimination simply referred to 'sex'), and they destabilise the truth of sex as something bodily and immutable.
By using this language (probably entirely unconsciously) the court has incorporated the precepts of gender identity theory into its ruling, even though it is careful to clarify that sex (at least in respect to title VII) refers to 'the biological distinctions between male and female'.
In her thread, Carter also discusses whether the court's reasoning in this case, if extended beyond employment, could be used to outlaw single-sex provision in other areas like homeless shelters and sports:
No doubt, some judges will decide the case means they can dismiss biology even though the M said it is not doing that. But my guess is that the court is headed toward narrowing the biology exception--but keeping it.
I'm not quite sure what she means by 'narrowing the biology exception - but keeping it'. But given that the overwhelming trend in the courts, the law and society has been to legally erase the significance of the sexed body altogether, I am fearful. And indeed Justice Alito, in his dissenting opinion, says the reasoning in this case could be used to effectively overturn Title IX and outlaw all single-sex provision:
The effect of the Court’s reasoning may be to force young women to compete against students who have a very significant biological advantage, including students who have the size and strength of a male but identify as female and students who are taking male hormones in order to transition from female to male.
Notice again how Alito incorporates the falsehoods of gender identity theory into his language even as he apparently rejects its logic: he refers to people who 'identify as female' or who 'transition from female to male'.
It's really incredible the way the language of 'gender identity' manages to scramble people's minds, rendering clear thinking on this subject impossible. Even Supreme Court justices - people whose professional lives have been dedicated to scrutinising arguments for logic, via the careful parsing of language - end up saying outright absurd things like 'transition from male to female', in direct contradiction to their own definition of those terms, without even realising what they are doing.
Full ruling with dissenting opinions here:
www.supremecourt.gov/opinions/19pdf/17-1618_hfci.pdf