In a landmark decision delivered on Wednesday, April 16, 2025, the United Kingdom Supreme Court has unanimously ruled that the legal definition of a “woman” under the Equality Act 2010 refers to biological female sex, determined at birth, dealing a significant setback to the transgender community.
This is as the ruling has excluded transgender women with Gender Recognition Certificates (GRCs) from being legally recognized as women under the Act, insisting that woman means biological female.
The top court in the UK gave the ruling on a lawsuit initiated by For Women Scotland (FWS), a gender-critical feminist group, against the Scottish government.
The legal dispute began in 2018 when the Scottish Parliament passed legislation aimed at increasing gender balance on public sector boards.
The law included transgender women with GRCs in the 50% female quota, prompting FWS to argue that this undermined sex-based rights for biological female.
FWS, in the lawsuit, contended that the Equality Act’s definition of “woman” should be tied to biological sex, not legal gender recognition.
The Scottish government, supported by trans rights advocates, argued that a GRC legally changes a person’s sex under the Gender Recognition Act 2004, entitling transgender women to the same protections as cisgender women.
However, the Supreme Court’s five judges, Lord Reed, Lord Hodge, Lord Lloyd-Jones, Lady Rose, and Lady Simler, unanimously rejected the position of the Scottish government, ruling that the Equality Act’s reference to “sex” pertains to biological sex, not acquired gender.
In an 88-page judgment, Deputy President Lord Hodge emphasized that the “concept of sex is binary” under the Equality Act, stating, “The terms ‘women’ and ‘sex’ in the Equality Act 2010 refer to a biological (female) woman and biological sex.”
The court clarified that transgender women, even those with GRCs, do not fall under the legal definition of a woman for the purposes of sex-based protections, such as access to single-sex spaces, maternity leave, or equal pay claims.
Part of the 88-page ruling reads: “The definition of sex in the Equality Act 2010 makes clear that the concept of sex is binary, a person is either a woman or a man.
“Persons who share that protected characteristic for the purposes of the group-based rights and protections are persons of the same sex and provisions that refer to protection for women necessarily exclude men.
“Although the word ‘biological’ does not appear in this definition, the ordinary meaning of those plain and unambiguous words corresponds with the biological characteristics that make an individual a man or a woman.
“These are assumed to be self-explanatory and to require no further explanation.
“Men and women are on the face of the definition only differentiated as a grouping by the biology they share with their group.”
However, the court stressed that the ruling does not strip transgender individuals of anti-discrimination protections.
The Supreme Court held that transgender people remain safeguarded under the Equality Act’s provisions for gender reassignment, protecting them from direct and indirect discrimination, as well as harassment in their acquired gender.
Lord Hodge urged against viewing the decision as a “triumph of one group over another,” emphasizing that the ruling aims to clarify legal definitions while preserving existing protections.
The ruling has a lot of implications for transgender women, particularly regarding access to single-sex spaces such as restrooms, changing rooms, domestic abuse refuges, prisons, and hospital wards.
Reacting to the Supreme Court ruling, a UK government spokesperson said: “We have always supported the protection of single-sex spaces based on biological sex.
“This ruling brings clarity and confidence, for women and service providers such as hospitals, refuges, and sports clubs.
“Single-sex spaces are protected in law and will always be protected by this government.”
Also, a Scottish Conservative leader, Russell Findlay, said the Supreme Court ruling is a victory for women across the United Kingdom.
Findlay stated: “(Scottish first minister) John Swinney now needs to respect women’s rights and get rid of the dangerous gender policies which have become embedded in Scotland’s public institutions.
“This ruling should sound the death knell once and for all for Nicola Sturgeon’s reckless self-ID plans, which Labour, the Liberal Democrats and the Greens shamefully backed to the hilt at Holyrood.”
The UK Conservative Party leader Kemi Badenoch, in her reaction, congratulated For Women Scotland and said the ruling is a “victory”.
She asserted: “Saying ‘trans women are women’ was never true in fact, and now isn’t true in law either.
“This is a victory for all of the women who faced personal abuse or lost their jobs for stating the obvious.
“Women are women and men are men: you cannot change your biological sex.”
UK’s Equality and Human Rights Commission (EHRC) also declared that it is happy with the court’s decision, but needs more time to consider the implications in full.
Chairwoman Baroness Kishwer Falkner stated: “We are pleased that this judgment addresses several of the difficulties we highlighted in our submission to the court, including the challenges faced by those seeking to maintain single-sex spaces, and the rights of same-sex attracted persons to form associations.”
