On 16 April 2025, in a landmark decision in the case of For Women Scotland Ltd (FWS) v The Scottish Ministers, the Supreme Court held that the terms “man”, “woman” and “sex” in the Equality Act 2010 (EqA) refer to biological sex. For the full judgment please click here. In this insight, we look at the reasons for that decision and key takeaways. 

The law 

The Gender Recognition Act 2004 (GRA) allows trans people to change their gender legally from their biological or birth sex to their acquired gender through the issue of a Gender Recognition Certificate (GRC). The GRA states that once a full GRC has been issued, a person's gender becomes, "for all purposes", their acquired gender. However, the GRA 2004 also provides that this rule does not apply to legislation where it would result in inconsistency. 

Gender reassignment and sex are protected characteristics under the EqA. The protected characteristic of sex is binary, referring only to a man or to a woman, and the EqA defines "woman" as "a female of any age". A trans person (with or without a GRC) will have the protected characteristic of gender reassignment, but the issue in this case was whether the definition of ‘woman’ in the EqA applies solely to biological sex, or if it also applied to ‘certificated sex’ or acquired sex (i.e. if it included a transwoman with a GRC).  

The facts of this case 

The Gender Representation on Public Boards (Scotland) Act 2018 (the 2018 Act) sets targets for increasing the proportion of women on public boards in Scotland.  The Scottish Parliament issued statutory guidance stating that a trans woman with a GRC brought them within the EqA definition of a “woman”, and so they could benefit from the 2018 Act. 

FWS brought judicial review proceedings to challenge the lawfulness of the statutory guidance. Outer House in 2022 and then the Inner House in 2023 held that the revised statutory guidance was correct and not unlawful on the basis that: 

• The GRA put in place a clear way for a person to change their sex in the eyes of the law and there was no distinction within the GRA between sex and gender.  
• The EqA has a clear and unambiguous definition of “woman” that does not explicitly exclude trans women with a GRC nor is it limited to biological sex.  

FWS appealed to the Supreme Court. 

The Supreme Court’s decision 

The Supreme Court unanimously upheld the appeal, finding that the only correct interpretation of the terms “man”, “woman” and “sex” in the EqA  is that they refer to biological sex, on the basis that:- 

• The Supreme Court was in no doubt that Parliament intended the words “man” and “woman” and “sex” in the Sex Discrimination Act 1975 (SDA) to mean biological sex. The GRA and the EqA did not, and were not intended to, modify their SDA meaning in any material way.  
• A biological approach is the only way to ensure that the meaning of sex and woman/man is consistent throughout the EqA. Any other interpretation “would render the EqA incoherent and impracticable to operate” by: 
  1. Creating inequality by giving trans people who possess a GRC greater rights than those who do not have a GRC. Also, employers and service providers would have no obvious means of distinguishing between the trans people who are protected and those who are not as they cannot lawfully ask someone whether or not they have a GRC. 
  2. Seriously weakening the protections given to those with the protected characteristic of sexual orientation for example by interfering with their ability to have lesbian-only spaces and associations. 
  3. Making provisions that can only be interpreted as referring to biological sex unworkable, for example, pregnancy and maternity.  
  4. Making the provision of separate spaces and single-sex services (including changing rooms, hostels and medical services), communal accommodation; 
• Similar impracticability arising in the operations of provisions relating to single-sex characteristic associations and charities, women’s fair participation in sport, the operation of the public sector equality duty, and the armed forces.

The Supreme Court concluded that the application of the ‘for all purposes’ rule in the GRA would make the protections from sex discrimination in the EqA “unworkable, inconsistent and incoherent”. Therefore, a trans person with a GRC in the female gender does not come within the definition of “woman” for the purposes of sex discrimination in the EqA. Consequently, the definition of woman in the Scottish Parliament’s statutory guidance on the 2018 Act is incorrect and unlawful. 

What to take away 

We recommend that all employers review their current EDI policies and training, and any other relevant policies, to ensure that they reflect the law as it now stands.  

The question of how these pieces of legislation interact, and specifically of whether a GRC is capable of changing a person’s sex for the purpose of the EqA, has been the subject of some uncertainty and considerable debate. 

This Judgment has provided clarity on the law and the statutory interpretation of “sex” under the EqA, whilst highlighting the protections afforded to both biological women and trans women. The Judgment makes clear that it is not seeking to define the meaning of the word “woman” other than when it is used in the provisions of the EqA but seeks to give clarity on the “meaning of the words which Parliament has used in legislating to protect women and members of the trans community against discrimination.”  

However, it does little to bring together those on either side of the ‘gender critical v trans’ debate. Individuals on both sides usually hold and express their polarised views in strong, sometimes controversial, ways.  Employers will still grapple with the increasingly difficult issues that such cases generate, notwithstanding the clarity on the provisions of the EqA. 

In consequence of the Judgment the Equality and Human Rights Commission has announced that a revised Code of Practice should be issued before the summer of 2025. Public bodies will need to take account of this in their capacity both as an employer and service provider, including in relation to any sex-differentiated/single sex services and facilities. In the meantime, organisations may face an increase in questions about their approach to such services and facilities for staff and members of the public, which will need to be managed appropriately. 

It is possible that employers may see an increase in claims under section 19A of the EqA (indirect sex discrimination claims), which can be brought by individuals who share the same disadvantage as a protected group (for example, biological women), even if they do not formally fall within it (for example, as a trans woman), as well as more claims of direct discrimination by association or perception and harassment. 

How Capsticks can help 

We have significant experience in supporting employers to prevent discrimination and harassment, including by drafting equality and diversity policies, codes of conduct and delivering training to employees at all levels.  

We also help organisations to manage concerns and difficult issues, deal with any complaints that may arise through conducting investigations, supporting decision makers and HR, and defending any employment tribunal claims brought regarding discrimination and/or harassment on the basis of protected beliefs. 

If you would like access to advice, training or need further guidance on these issues or a specific case, please contact Nicola Green, Jonathan Lewis and Alistair Kernohan.