The Supreme Court decision in For Women Scotland Ltd v The Scottish Ministers

Last week the UK Supreme Court delivered its unanimous judgment in the case of For Women Scotland Ltd v The Scottish Ministers, allowing the appeal and addressing the interpretation of the Equality Act 2010 in relation to gender reassignment and sex discrimination. David Welsh considers the outcome.

In For Women Scotland Ltd v The Scottish Ministers [2025] UKSC 16, For Women Scotland Ltd, a feminist organisation, challenged the statutory guidance issued by the Scottish Ministers under the Gender Representation on Public Boards (Scotland) Act 2018 (the 2018 Act). The guidance stated that a trans woman with a full Gender Recognition Certificate (GRC) should be treated as a woman for the purposes of achieving the gender representation objective of 50% women on public boards. For Women Scotland argued that this interpretation was unlawful and outside the legislative competence of the Scottish Parliament.

The Supreme Court permitted four parties to intervene and permitted two of those four parties to make oral submissions at the hearing. The Supreme Court singled out the written and oral submissions made on behalf of Sex Matters Limited at paragraph 35 of the judgment, noting that they “gave focus and structure to the argument”.

Key issues

The central question was whether the Equality Act 2010’s (EA 2010's) references to “sex,” “man,” “woman,” “male,” and “female” should be interpreted in light of the Gender Recognition Act 2004, which allows a person to change their legal sex by obtaining a GRC. In particular, the Supreme Court examined whether the EA 2010 makes provision within the meaning of section 9(3) of the GRA 2004 to displace the application of section 9(1), which states that a person’s gender becomes their acquired gender for all purposes upon obtaining a GRC.

The Supreme Court emphasised the importance of clarity and consistency in statutory interpretation, particularly for an Act like the EA 2010, which regulates practical day-to-day conduct across various sectors and therefore must readily be understandable by those on whom it places obligations.

Biological v certificated sex

In a detailed judgment, the Supreme Court analysed the definitions of “sex,” “man,” and “woman” in the EA 2010, concluding that these terms refer to biological sex. The Supreme Court found that interpreting “sex” as certificated sex would create incoherent and unworkable provisions, particularly in relation to pregnancy and maternity discrimination, single-sex services, communal accommodation, and sports.

Gender reassignment and sexual orientation

The distinct and separate protections for gender reassignment and sexual orientation in the EA 2010 were also discussed by the Supreme Court. It noted that conflating these characteristics with certificated sex would create two sub-groups within those who share the protected characteristic of gender reassignment, giving greater rights to those with a GRC.

While the decision emphasises biological sex in the context of sex discrimination, it does not diminish the protections available to trans people under the EA 2010. Trans individuals remain protected from discrimination based on gender reassignment and can still bring claims for direct and indirect discrimination, harassment, and victimisation in reliance on principles such as associative and perceived discrimination.

Positive action and the Public Sector Equality Duty

The Supreme Court also discussed the positive action provisions and the Public Sector Equality Duty (PSED) in the EA 2010, which aim to address the needs and disadvantages of groups with shared protected characteristics. The Supreme Court found that a certificated sex interpretation would undermine the ability to conduct robust analysis and address the distinct needs of women and trans people separately.

Conclusion

The Supreme Court concluded that the EA 2010 makes provision within the meaning of section 9(3) of the GRA 2004, displacing the rule in section 9(1). The terms “sex,” “man,” and “woman” in the EA 2010 refer to biological sex, not certificated sex. Consequently, the Scottish Government’s guidance was deemed incorrect, and the definition of “woman” in the 2018 Act is limited to biological women.

This decision has significant implications for the interpretation of anti-discrimination law in the UK, ensuring that the protections afforded by the EA 2010 are applied consistently and coherently. The decision underscores that while the GRA 2004 allows individuals to change their legal gender, this change does not affect the interpretation of sex in the EA 2010. This maintains a clear distinction between gender reassignment and biological sex in anti-discrimination law.

Public authorities must consider the distinct needs and disadvantages of biological women and men separately from those of trans people. This ensures that policies and practices aimed at promoting equality and eliminating discrimination are based on clear and consistent definitions.

Organisations and public bodies may need to review and adjust their policies and practices to align with this interpretation of the EA 2010. This includes ensuring that single-sex services and positive action measures are correctly applied based on biological sex.

Overall, the Supreme Court’s decision provides clarity on the interpretation of sex in anti-discrimination law, reinforcing the distinction between biological sex and gender reassignment while ensuring that all groups receive appropriate protections under the law.

David Welsh is a barrister at Cornerstone Barristers specialising in public law. Since being called to the bar in 2017, David has appeared in courts at all levels, including before a full bench of the UK Supreme Court and a full bench of the Court of Justice of the European Union. David has a busy public law practice, including high-profile constitutional litigation.

Sex Matters Limited instructed David, led by Ben Cooper KC of Old Square Chambers.