Insights

Supreme Court rules on meaning of "sex" in the Equality Act

24/04/2025

In a judgment which has been celebrated by some and received with alarm by others, the Supreme Court has given a definitive ruling on the meaning of “sex”, “man” and “woman” in the Equality Act 2010.  This question has become increasingly loaded in the public debate over trans identities and rights.   Although the Supreme Court decision provides clarity over the law, it leaves many practical issues for employers still unresolved. 

Background to the case 

The case arose from guidance issued by the Scottish Government about gender balance on public boards.   The guidance (which had already been revised following a previous challenge) referred to the Equality Act 2010, but stated that individuals with a gender recognition certificate recognising them as a woman should be treated as women for the purposes of the guidance.  A feminist campaign group challenged this aspect of the guidance as being incorrect in law. 

The Supreme Court decision 

The question for the Supreme Court boiled down to whether the term “sex” in the Equality Act (and the words “man” and “woman”) referred to “biological sex” (i.e. sex at birth) or “certificated sex” (i.e. sex as recognised under a gender recognition certificate).   

It's worth bearing in mind that only a small number of individuals have gender recognition certificates - far fewer than the number describing themselves as trans or non-binary across the population.  The Gender Recognition Act states that a gender recognition certificate changes the person's sex “for all purposes”, but that this is subject to any contrary provision in legislation.  The Supreme Court held that this does not require an explicit statement in any legislation disapplying the effect of a certificate - it's a question of interpreting legislation to assess whether it upholds or displaces the effect of a gender recognition certificate. 

Having set out the legal approach, the Supreme Court then held that, in the Equality Act, “sex” refers to biological (birth) sex - i.e. displacing the general rule that a gender recognition certificate alters the person's sex for all purposes.  The reasoning for this was, in summary: 

  • the legislation which preceded the Equality Act, the Sex Discrimination Act, used the words “man”, “woman” and “sex” with their biological meaning, and the Equality Act did not alter their meaning;  
  • those words needed to have a consistent meaning in the Equality Act in order for the Act to be coherent and workable - the meaning could not alter depending on the context;
  • the sex discrimination provisions of the Equality Act, particularly those referring to pregnancy, childbirth, maternity leave and breast-feeding, can only be interpreted, logically, as referring to biological sex; and
  • some aspects of the Act (including provision for single and separate sex services and associations) would be unworkable if they referred to certificated sex rather than biological sex.

Implications for employers 

The Court was at pains to emphasise that, in their view, this interpretation does not reduce the legal protection for trans people, who continue to be protected under the separate protected characteristic of gender reassignment and, depending on the circumstances, may also be able to bring claims based on their perceived sex, their actual or perceived sexual orientation, their association with one sex (associative discrimination) and harassment claims.   None of these potential claims would be dependent on a gender recognition certificate. 

However, the judgment does mean that a trans woman (whether or not she had a gender recognition certificate) could not bring a sex discrimination or equal pay claim comparing herself to a male comparator.   It also has significant implications for trans participation in single-sex sports, associations and services, as well as positive action aimed at women.   

The Equality and Human Rights Commission will be updating its statutory Code of Practice to reflect the judgment, expected this summer, which will be helpful to employers and service providers.  

Workplace facilities 

The case throws into sharp relief the lack of clarity in the law around use of changing and toilet facilities at work.  Whether employers allow trans staff to use the toilets appropriate to their gender identity, require them to use those applicable to their biological sex or seek to provide an alternative, they may face potential claims from trans staff, female staff (such as the claim currently being brought by Sandie Peggie) or staff with a protected belief who object to sharing facilities with a trans colleague.   There are no easy answers here and the law in this area is complex and uncertain. 

Gender recognition certificates

The case focused on the position of individuals with gender recognition certificates.  However, employers should remember that, in most cases, it is unnecessary and inappropriate to ask for an individual's certificate (save in limited circumstances such as right to work checks) and it is a criminal offence to disclose information relating to a certificate except in limited circumstances. 

Although it concerns a rather technical point of interpretation, the Supreme Court's judgment has been the focus of intense media interest as well as concern from LGBTQ organisations. Employers should consider how best they can support staff and reaffirm their commitment to an inclusive workplace, while also ensuring that they review policies and practices in light of the judgment to ensure legal compliance.   We will be providing updates and more guidance on this as the position evolves and when the EHRC guidance is updated. 

 

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