Supreme Court Clarifies the Legal Definition of a “Woman”

The UK Supreme Court has confirmed that under the Equality Act 2010, the word “woman” refers to biological sex. This ruling comes from the case For Women Scotland v The Scottish Ministers and has important consequences for how employers interpret equality law in the workplace.

What was the case about?

Although the case itself was focused on public board appointments in Scotland, the outcome has much wider implications. The Scottish Government had issued guidance that allowed trans women with a Gender Recognition Certificate (GRC) to count towards the target of increasing the number of women on non-executive public boards. This guidance was challenged by the campaign group For Women Scotland.

Their legal argument was that the Equality Act defines “woman” based on biological sex, and that the Scottish Government’s position conflicted with that definition.

The Court’s decision

The Supreme Court ruled that:

• Under the Equality Act 2010, sex is defined biologically.
• A trans woman, even one with a GRC, is not considered a woman under this particular law.
• The terms used in the Act must be consistent in order to avoid confusion or legal uncertainty.

The judges said that allowing the meaning of “woman” to change depending on context would make the law unpredictable and difficult to apply.

The Court’s decision means that when organisations apply the protected characteristic of sex under the Equality Act, they must do so based on biological sex. This affects how employers should interpret rights, protections and initiatives that are linked to being male or female.

For example, workplace policies or practices that relate specifically to women, such as gender-specific training or maternity protection, need to be based on biological sex. This is to ensure that the application of the law remains consistent and legally compliant.

A particularly sensitive issue for many employers is the provision of toilet and changing facilities. The Workplace (Health, Safety and Welfare) Regulations 1992 require separate toilet facilities for men and women unless each toilet is in a private, lockable room.

The Supreme Court did not specifically address toilet provision, but the logic of the ruling suggests that biological sex is likely to apply in this context too. This means that employers are within their rights to limit the use of single-sex spaces based on biological sex, provided they do so lawfully and with consideration.

Review your equality and inclusion policies – make sure your policies correctly reflect the legal definitions of protected characteristics, especially sex and gender reassignment.

Ensure respectful internal communication – be mindful in how this legal change is explained to staff. Language should remain professional and respectful, and managers may need support to handle questions confidently.

Review facilities and workplace practices – if you have single-sex toilets or changing rooms, assess whether they are being used in a way that meets your legal obligations and reflects your updated policy.

Support your people – this ruling may be difficult for some employees, especially those who are transgender or non-binary. Consider what support you can offer or whether it would be helpful to signpost people to external organisations.

Keep up to date with further guidance – the Equality and Human Rights Commission is expected to issue new guidance over the summer. This may help clarify how employers can apply the law in practice.

The Supreme Court has confirmed that for the purposes of the Equality Act 2010, sex means biological sex. While this brings clarity from a legal standpoint, it also introduces practical challenges. Employers will need to navigate these issues with care, balancing legal compliance with a supportive and respectful approach to managing people.

If you would need help reviewing your workplace policies or discussing next steps, our team of HR and employment law experts are here to support you get in touch today at support@hr-inspire.com