2025 Supreme Court Ruling

What Does the Definition of “Woman” Mean for Employers?

A recent Supreme Court ruling has clarified how the term “woman” should be interpreted under the Equality Act 2010. The decision confirms that, in legal terms, “woman” refers to biological sex and not gender identity, even where an individual holds a Gender Recognition Certificate (GRC).

This has raised important questions for businesses, particularly those committed to diversity and inclusion, and those operating single-sex spaces or initiatives.

What will this ruling mean in practice for employers?

The Background

The case was brought by the campaign group For Women Scotland, which challenged the Scottish Government’s approach to defining “woman” in legislation aimed at improving gender balance on public boards. The Scottish Government had included transgender women with GRCs within the definition of “woman”. The Supreme Court unanimously ruled that this interpretation went beyond the meaning of “woman” under the Equality Act 2010.

The Court stated that the term “sex” in the Act refers to biological sex, and that this understanding is necessary to preserve the coherence of the law in areas such as pregnancy, maternity, and single-sex services.

Where the Ruling Applies

The Equality Act 2010 is a UK-wide law (excluding Northern Ireland, which has its own legal framework), and the Supreme Court is the highest authority on its interpretation. This means the ruling applies to:

• England
• Wales
• Scotland

Employers across these nations are legally bound to apply the law in line with this decision.

Implications for Employers and Businesses

HR Policies and Diversity Programmes

Businesses should review any policies or schemes that refer specifically to “women”, such as leadership development initiatives or mentoring programmes. If these are based on biological sex, employers must be clear about eligibility. Where businesses wish to include trans women in such initiatives, it should be clearly stated and justified within the scope of broader equality and inclusion goals.

Single-Sex Spaces and Facilities

Employers who provide single-sex facilities, such as toilets, changing rooms or sleeping accommodation, may restrict access based on biological sex where it is a proportionate means of achieving a legitimate aim. The ruling strengthens the legal foundation for maintaining such spaces, although any decisions must still be handled sensitively and with a clear rationale.

Diversity and Inclusion Strategy

While the legal definition of “woman” is now confirmed as relating to biological sex, gender reassignment remains a protected characteristic under the Equality Act. Employers are still legally obliged to treat transgender individuals fairly and must not discriminate against them.

This may create tensions between legal compliance and organisational values around inclusivity. Clear policies and careful communication will be key in navigating these issues.

Staff Training and Communication

It is advisable for employers to update diversity training and ensure managers and staff understand the difference between legal obligations and inclusion efforts. Supporting trans employees in the workplace continues to be a best practice, even though the law now sets clearer limits around sex-based definitions.

Public Messaging and Campaigns

Businesses involved in external campaigns, sponsorships, or events that focus on women’s participation or representation should consider how this ruling may affect eligibility criteria and messaging. Consistency and clarity will be important, particularly in sensitive or public-facing contexts.

Final Thoughts

This ruling does not remove legal protections for transgender individuals, nor does it prohibit inclusive practices in the workplace. However, it does clarify that where the law refers to “woman” in the context of the Equality Act, it means biological sex. Employers should take this opportunity to review internal policies, ensure compliance, and continue fostering inclusive environments within the bounds of the law. Seeking legal advice where necessary is strongly recommended.

If your organisation would benefit from guidance or policy review in light of this decision, please get in touch for tailored advice.

Get in touch with our team today

E: BusinessGroup@allingtonhughes.co.uk

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