On 16th April 2025, the Supreme Court handed down a significant ruling on the definition of “sex” within the Equality Act 2010.

This judgment came in respect of a long-fought dispute between campaign group For Women Scotland (FWS) and the Scottish Government, following the introduction of the Gender Representation on Public Boards (Scotland) Act 2018.

The main contention was how the Gender Recognition Act 2004 interplays with the Equality Act 2010 when it comes to the definition of “sex”.

The unanimous decision of the court was that the terms “man”, "woman" and "sex" in the Equality Act 2010 refer to biological sex, concluding any other interpretation of the terms would render the Act incoherent and impracticable to operate.

To come to its conclusion, the Court had to consider the interpretation of both Acts and found the following:

• The Gender Recognition Act 2004 allows for the rule that a Gender Recognition Certificate (GRC) changes someone’s sex “for all purposes” to be disapplied by provisions in other legislation.

• The meaning of “sex” within the Equality Act 2010 needs to be consistent and, amongst other things, allowing certificated sex would blur the lines of the definitions of “man” and “woman”, making the protected characteristic of “sex” incoherent.

• Allowing a “certificated sex” interpretation would create two sub-groups for those who share the protected characteristic of gender reassignment, with those with a GRC having greater rights than those who don’t.

This judgment only specifically covers the definition of these terms in the Equality Act. As the judgment notes, it is not intended to weigh in on the arguments in the wider public domain on the meaning of gender or sex.

Importantly, the judgment does not remove protection from discrimination for transgender people, with or without a GRC. Transgender people are still protected under the Act through the protected characteristic of gender reassignment and may also claim discrimination in their acquired sex.

It is now expected that the EHRC will update its guidance on the practical impact of the ruling on, amongst other things, single sex spaces.

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