Supreme Court Clarifies Legal Definition of “Woman” Under Equality Act 2010
Published byLiam A Entwistle
A landmark ruling from the UK Supreme Court has clarified a long-standing area of uncertainty in equality law – confirming that, for the purposes of the Equality Act 2010, the term “woman” refers to biological sex and does not include transgender women, even if they hold a Gender Recognition Certificate (GRC).
The decision, handed down unanimously by the Court, follows years of legal and political debate. While the ruling is likely to spark strong reactions from various groups, it brings much-needed legal certainty for employers, service providers and public bodies when it comes to interpreting sex-based rights and provisions.
What was the case about?
The Court was asked to consider whether the definition of “woman” in the Equality Act could include transgender women who have obtained a GRC. It concluded that it could not – ruling that the protected characteristic of sex under the Act relates strictly to biological sex at birth.
The judges warned that introducing different interpretations based on whether or not someone held a GRC would lead to “heterogeneous” groupings – a term used to describe categories that are legally unclear and inconsistent – and would undermine the overall coherence of the Act.
What does this mean in practice?
The judgment has important implications for employers and service providers, particularly in relation to single-sex spaces and services. The Court made clear that in contexts where sex-based separation is permitted or required – such as changing rooms, hostels, communal accommodation, or certain healthcare services – biological sex should be the basis on which decisions are made.
It also highlighted areas where this interpretation will be especially relevant, including:
• Women’s participation in sport
• The operation of single-sex charities and associations
• The public sector equality duty
• Service provision within the armed forces
There was criticism within the judgment of both the Scottish Government and the Equality and Human Rights Commission, both of which had previously taken the view that people with a GRC should be considered legally as their acquired gender. The Court rejected this approach, noting the practical challenges it could create, especially where GRC status is private and not publicly known.
What about protections for trans people?
Crucially, the Court emphasised that its decision does not reduce or remove legal protections for transgender individuals. People who have undergone, are undergoing, or intend to undergo gender reassignment remain protected under the separate protected characteristic of gender reassignment in the Equality Act.
The Court also cautioned against using the decision as a political weapon, urging all sides not to frame it as a victory for one group over another.
What should employers do now?
In light of this clarification, employers should take the opportunity to review any single sex provisions, services or spaces, and take advice on any outstanding issues, such as toilet access for transgender employees.
Keep an eye on how employees are reflecting on or discussing the decision, and that the lines on harassing behaviour are not being crossed. Remind employees about your equal opportunity and bullying and harassment policies.
WJM’s Employment Law team is on hand to help. Get in touch a member of our team for guidance: employment@wjm.co.uk
The information contained in this newsletter is for general guidance only and represents our understanding of relevant law and practice as at April 2025. Wright, Johnston & Mackenzie LLP cannot be held responsible for any action taken or not taken in reliance upon the contents. Specific advice should be taken on any individual matter. Transmissions to or from our email system and calls to or from our offices may be monitored and/or recorded for regulatory purposes. Authorised and regulated by the Financial Conduct Authority. Registered office: 319 St Vincent Street, Glasgow, G2 5RZ. A limited liability partnership registered in Scotland, number SO 300336.
