On Wednesday, the United Kingdom’s Supreme Court ruled that transgender women do not fit the legal definition of “woman.”
Justice Patrick Hodge clarified that all five judges agreed that “the terms ‘woman’ and ‘sex’” in the country’s Equality Act, established in 2010, “refer to a biological woman and biological sex.”
“The Equality Act 2010 gives transgender people protection, not only against discrimination, but through the protected characteristic of gender reassignment," he said, asserting that a person who “identifies” as transgender person with documentation recognizing them as female should not be considered a woman for equality purposes.
UK Supreme Court rules that a ‘woman’ in UK law refers to biological sex and a transgender man is not a woman by legal definition.
— Oli London (@OliLondonTV) April 16, 2025
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According to the New York Post, this definition was debated beginning in 2018 (via NYP):
The definition was challenged in 2018 after the Scottish Parliament passed a law stating that women should make up 50% of the representatives on Scottish public boards.
Scottish officials later said female representation included trans women with a Gender Recognition Certificate, which offers legal recognition of someone’s female sex under the Equality Act, to meet the quota.
Women Scotland (FWS), the women’s rights group that brought the legal challenge, argued the Scottish officials’ redefinition of women went beyond Parliament’s powers.
“Not tying the definition of sex to its ordinary meaning means that public boards could conceivably comprise 50% men, and 50% men with certificates, yet still lawfully meet the targets for female representation,” the group’s director, Trina Budge, had previously said.
This legal challenge was reportedly rejected in 2022, but the plaintiffs were permitted to take the challenge to the nation’s high court.
Going forward, this landmark ruling could impact sex-based rights and single-sex facilities across the country, clarifying that men who masquerade as women cannot enter women’s spaces.