Hello and welcome back to this week’s case of the week.  If you missed last week’s case on Kinch v Compassion in World Farming International, please click here to read it. This week, we look at the landmark ruling in For Women Scotland Ltd v The Scottish Ministers [2025] UKSC 16. At the heart of this decision was a question that has divided policy, public opinion, and practice for years: Does “sex” under the Equality Act 2010 include the acquired gender of a person with a Gender Recognition Certificate (GRC)?

Background

The case was based on the Gender Representation on Public Boards (Scotland) Act 2018, which aimed to ensure 50% female representation on public boards. The Scottish Government’s guidance included trans women with GRCs in this proportion. For Women Scotland (FWS), a gender-critical advocacy group, challenged this inclusion, arguing that it conflated the distinct protected characteristics of sex and gender reassignment under the Equality Act 2010.

Initially, the Court of Session in Scotland upheld the Scottish Government’s guidance. However upon appeal, the UK Supreme Court reversed this decision, stating that the Equality Act’s references to “sex” pertain strictly to biological sex.

Supreme Court Judgment

The Supreme Court’s unanimous decision emphasised that interpreting “woman” to include trans women with GRCs would create legal inconsistencies and undermine protections based on biological sex, such as those related to pregnancy, maternity, single-sex spaces, and sport. Provision of single sex spaces for toilets and changing rooms is a specific legal duty under Health and Safety regulations.

The Court clarified that sex and gender reassignment are separate protected characteristics under the Equality Act. Despite affirming protections against discrimination for trans individuals, the Court concluded that appointing a trans woman with a GRC does not fulfil statutory requirements for the representation of women under the 2018 Act.

The Supreme Court ruled that references to “sex”, “woman”, and “man” in the Equality Act 2010 mean biological sex.

This means that only biological women are protected as “women,” and trans women with a GRC, are not included in this category in the Act.

Although individuals who transition and obtain a GRC change their legal sex under the Gender Recognition Act 2004, this change does not apply when interpreting the protected characteristic of sex under the Equality Act.

The ruling clarifies what many already thought. Single sex spaces such as prisons, toilets and gay bars can be limited to those of the same biological sex.

The ruling only impacts those who followed Guidance in Scotland, or guidance promulgated by Stonewall in England and Wales. If you as an organisation interpreted single sex provision to include certificated sex, you now need to change your policy.

If however, you have interpreted single sex to be limited to biological sex you have nothing further to do. You are compliant. You interpreted the law correctly and have not been misled by Guidance.

Gender reassignment remains a separate protected characteristic. Trans people are still protected by the Equality Act, but not on the basis of the acquired sex.

The GRC does not override biological sex in the context of employment, recruitment, the provision of services or positive action under the Equality Act.

The Court also ruled the Scottish Government’s guidance was unlawful and based on a legal error.

Takeaway Points

Policies that refer to “women” or “men” for legal compliance (e.g. positive action, quotas, or reporting under the public sector equality duty) must now be based on biological sex, not gender identity or a GRC.

This ruling does not remove protection from trans individuals. They remain covered under the gender reassignment characteristic and must not face direct or indirect discrimination, harassment, or victimisation.

A trans woman with a GRC is not considered a woman under the Equality Act when it comes to protections based on “sex”. This applies in contexts such as single-sex services, recruitment drives targeting women, or sex-based occupational requirements.

Even though sex in law means biological sex for Equality Act purposes, asking someone whether they are trans or whether they have a GRC can still be legally risky or unlawful. Confidentiality around gender status must still be maintained under the GRA 2004 and data protection laws.

While legal definitions are now stricter, employers should continue to respect and support trans identities whilst also recognising that women’s right to single sex spaces must be respected.