"""
Judges at the Supreme Court in London were asked to rule on what that law means by "sex" - whether it means biological sex, or legal, "certificated" sex as defined by the 2004 Gender Recognition Act.
[quoted out of order]
The UK Supreme Court has unanimously backed the biological definition of "woman" under the 2010 Equality Act.
[...]
They said a "certified" definition of sex would weaken protections for lesbians, citing the example of lesbian-only spaces and associations as it would mean that a trans woman who was attracted to women would be classed as a lesbian.
[...]
The judges added: "The practical problems that arise under a certificated sex approach are clear indicators that this interpretation is not correct."
"""