In a landmark judgment (UK Supreme Court Judgment: For Women Scotland Ltd v The Scottish Ministers [2025] UKSC 16) that is set to influence sex and gender law for years to come, the UK Supreme Court has decided that the Equality Act 2010 defines “woman” and “sex” by biological sex — not by legal gender identity, or the possession of a Gender Recognition Certificate (GRC).
The case, For Women Scotland Ltd v The Scottish Ministers, asked if the Scottish Government could expand the legal definition of “woman” for public board appointments. The Court gave a firm no.
To why the Supreme Court woman definition matters, let’s explore the ruling and its legal impact.
The Background: Who Can Be Counted as a “Woman” on Public Boards?
The Gender Representation on Public Boards (Scotland) Act 2018 was sort to boost the number of women on public boards. Initially, official guidance defined “woman” broadly. It included those “living as a woman” and individuals undergoing gender reassignment.
After courts ruled the first version unlawful (FWS1), the Scottish Government published new guidance. It aligned the term “woman” with the Equality Act 2010, which defines a woman as “a female of any age” (EA 2010, s.212). Nevertheless, the guidance also included trans women with a GRC.
FWS disagreed. They argued that “woman” means biological female. In their view, trans women (even with a GRC) do not meet that legal definition.
The Supreme Court’s Verdict
The Court unanimously allowed the appeal. It ruled:
“The meaning of the terms ‘sex’, ‘man’ and ‘woman’ in the EA 2010 refer to biological sex, as any other interpretation would render the EA 2010 incoherent and impracticable to operate.” – [264]
Therefore, the Scottish Ministers’ guidance was incorrect. Thus, the Supreme Court woman definition rejects including trans women with a GRC under either the Equality Act or the 2018 Act.
Core Legal Reasoning and Key Quotes (with Paragraph References)
Sex in Law Means Biological Sex
“As a matter of ordinary language, the provisions relating to sex discrimination can only be interpreted as referring to biological sex.” – [168]
“Interpreting ‘sex’ as certificated sex would cut across the definitions of ‘man’ and ‘woman’ and thus the protected characteristic of sex in an incoherent way.” – [172]
The Court stressed that allowing a different meaning of “woman” in different sections of the Equality Act would be “absurd”:
“The Court rejects the suggestion of the Inner House that ‘woman’ and ‘sex’ can refer to biological sex in some sections of the EA 2010, and certificated sex in others.” – [189]
Why a Biological Meaning Is Required
The Court provided examples:
- Pregnancy:
“Only biological women can become pregnant. Therefore, these provisions are unworkable unless ‘man’ and ‘woman’ have a biological meaning.” – [177]
- Single-Sex Spaces:
“Separate spaces and single sex services… including changing room hostels and medical services… require a biological interpretation of ‘sex’ in order to function coherently.” – [211]
- Education, Sport, Armed Forces:
“Similar confusion and impracticability arise… in relation to single sex higher education institutions [226], sport [232], the public sector equality duty [237], and the armed forces [245].”
Does the Gender Recognition Act Override This?
“Section 9(3) of the GRA 2004 allows the rule in section 9(1) to be disapplied… where the term context and purpose of the relevant legislation show that it does.” – [99]
“The EA 2010 is such a provision.” – [264]
Put simply, even if someone holds a GRC, it does not change the meaning of “woman” in the EA 2010. Particularly when applying that change would break the law’s functionality.
Equality Must Be Practical
“It is important that the EA 2010 is interpreted in a clear and consistent way… so that those who are subject to its obligations can perform them in a practical way.” – [151]
“A certificated sex interpretation would… create two sub-groups within those who share the protected characteristic of gender reassignment… Those seeking to perform their obligations… would have no obvious means of distinguishing between the two.” – [198]–[203]
What This Means for Family Law in England
This case isn’t just about public boards. It directly impacts many areas of family and equality law, including:
-
Women-Only Spaces
Support services like domestic abuse refuges, single-sex hostels and women’s health clinics can continue offering protection based on biological sex.
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Legal Clarity Around Parental Rights
Provisions relating to maternity, pregnancy, and parenting will remain rooted in biological sex, as intended by Parliament.
“The provisions relating to pregnancy and maternity… are based on the fact of pregnancy and giving birth to a child.” – [177]
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Fairness in Associations and Education
Associations or institutions aimed at biological women—including sports teams and universities—now have clearer legal support to maintain, sex-based membership rules.
What About Trans People?
The Court was clear: This ruling does not strip trans people of protections.
“Trans people are protected from discrimination on the ground of gender reassignment.” – [248]
“A trans woman can claim sex discrimination because she is perceived to be a woman.” – [259]
So, while the Supreme Court woman definition rests on biological sex, trans people remain legally protected.
Final Thoughts: Legal Clarity, Not Exclusion
This judgment is about ensuring consistency, not exclusion. It helps the law function reliably. The Court has clarified that the meaning of “woman” in sex-based protections cannot be stretched to include individuals who are not biologically female, even if they possess a GRC.
In the words of the Court:
“The meaning of the terms ‘sex’, ‘man’ and ‘woman’ in the EA 2010 refer to biological sex… any other interpretation would render the EA 2010 incoherent and impracticable to operate.” – [264].
For women’s advocates, lawyers, and policymakers, this ruling reaffirms Parliament’s intent and strengthens legal certainty when sex is a relevant factor.
Full Case Citation: For Women Scotland Ltd v The Scottish Ministers [2025] UKSC 16.
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