The Supreme Court’s Decision on the meaning of ‘woman’ under the Equality Act.

On 16 April 2025, the Supreme Court unanimously ruled that for the purposes of the Equality Act 2010, the words ‘woman’, ‘man’ and ‘sex’ refer to biological sex at birth. So that, for example, trans women (biological males) remain men for the purposes of discrimination law.  This provides legal clarity on what has been a highly contentious issue.   In the last week, there has been a deluge of commentary on the decision, much of which has been confusing and contradictory.   The ruling also throws up some very practical considerations  for employers, especially since guidance on the issue to date has operated on a different footing.

We aim to distil the court’s findings, what they mean for employers and outline some practical considerations and steps for employers to take.

The Court’s Decision

The issue arose in the context of positive action measures taken by the Scottish Government for the appointment of women to the boards of certain public authorities - the objective was to have 50% of non-executive board members who were women. The question for the court was whether trans women (ie, biological males) in possession of a Gender Recognition Certificate (GRC), should count towards the target.  A GRC operates to change a person’s gender for legal purposes and involves a fairly rigorous application process, including having lived in the acquired gender for 2 years and producing medical evidence.   The vast majority of trans people do not possess a GRC, so the decision itself affected a fairly small section of the trans population, however, the impact of the decision goes far wider.

In deciding this issue, the court had to interpret the definitions of ‘sex’ and ‘woman’, as defined by the Equality Act.    The court said it was clear for these purposes that sex is a binary concept, a person is either a woman or a man, and an interpretation which included someone’s ‘certified’ sex, would cut across the definition in an incoherent way.  The court cited provisions in the Act relating to pregnancy and maternity discrimination, which only makes sense if sex is given its biological meaning. Since only biological women can become pregnant, the protection is necessarily restricted to them.  It also pointed to the fact that the gender reassignment provisions in the Equality Act provide separate protections for trans people, distinct from sex.  

Other provisions which the court stated depend on a biological interpretation of sex and which would otherwise be both incoherent and unworkable, include certain exemptions from discrimination under the Equality Act.  Notably, the provision of single sex services and facilities (for example changing rooms, segregated women areas in hostels, separate medical or counselling services and domestic violence refuges), which would otherwise be discriminatory, are permitted in certain circumstances provided they are a proportionate means of achieving a legitimate aim.  If sex meant ‘certified’ sex,  the service provider would have to allow access to trans women with a GRC ( ie biological males), however, they could refuse access to trans women without a GRC.   The court pointed out that a woman only hospital ward might, for example, object to the presence of biological males but it is difficult to see how the reasonableness of such an objection could be founded on possession or lack of a certificate. They would essentially be creating a hierarchy between those trans women who possess a GRC and those who do not. On a purely practical level, this would be difficult to police especially since the possession of a GRC is confidential.

Protection from Discrimination for Trans People Remains

The court’s ruling does not deprive trans people of protection from discrimination.    The court pointed out that discrimination because of a protective characteristic can be based on perception. For example, a trans woman (a biological male) could claim sex discrimination because she was perceived to be a woman and as a result did not get offered a job that would have been awarded to her had she been a man. Her case does not depend on her actual sex but on the perception and motivations of the discriminator.

Likewise for a harassment claim, it is necessary only to establish a sufficient link between the harassing conduct and the relevant protective characteristic, the victim does not have to possess that characteristic. So, for example, a trans woman who presents and is perceived as a woman at work and who is harassed by comments about the way that she looks, could bring a claim for harassment related to sex.

Trans people are also protected from discrimination on the basis of gender reassignment.

From an employer’s perspective, the duty not to discriminate on the grounds of sex, gender reassignment or any other protective characteristic remains and employers should continue to comply with their policies and legal guidance in this regard.

Single Sex Spaces and Facilities

Where the ruling is likely to have a significant impact is in relation to the provision of single sex facilities and services.  These may be provided where appropriate and proportionate to do so (including toilets, changing rooms, hostels and medical services).  

In the context of the workplace this is likely to be most relevant in relation to toilets and changing facilities.  

Health and safety legislation requires that there are adequate facilities for all employees.   Smaller workplaces with only single occupancy toilets, which are not split based on sex are unlikely to have an issue.  However, the practical reality is that very many workplaces have separate provision for male and female staff.   Prior to this ruling, the common practice has been to allow people to use facilities which match their acquired gender.   It is now clear that single sex facilities must be provided according to biological sex. This clearly poses a practical dilemma for trans people and for employers. Trans women are far more likely to prefer using female-only toilets and may also be afraid that they will prompt objections if they enter men’s facilities.  There is also the risk of effectively ‘outing’ those trans people who would rather keep their history private, by requiring them to use facilities based on their birth sex. 

One solution is for employers to provide additional gender neutral spaces alongside single sex ones.  However, whether or not this is possible is likely to come down to a question of resources and physical space.    Simply changing signage to ‘gender neutral’ will not be sufficient as health and safety regulations require specific configurations for gender neutral facilities.

Other Workplace Issues

Employers should be aware that tensions in the workplace may run high as a result of this ruling, with the potential for conflict between different individuals and groups and in particular trans people and those with gender critical beliefs.   Both these groups are protected under the Equality Act and any conflicts will require careful handling and involve balancing respect for differing opinions and beliefs and protection of staff from harassment.

Employers also owe a duty of care which extends to the psychological well-being of their staff, some of whom may feel especially vulnerable as a result of the ruling.

Practical Guidance For Employers

The EHRC has announced it will update its guidance in the light of the court’s ruling.  In the meantime, the following are some practical steps for employers to consider:

1.      Remind staff of existing policies and protections from discrimination and harassment and their obligations under these.  

2.      Explain any practical changes arising from the ruling, eg, in relation to use of single sex facilities.

3.      Engage with affected groups to understand concerns and find practical solutions.

4.      Look at current facilities (toilets/changing rooms) and assess whether anything should and can be changed in light of the ruling.  If possible, a mix of facilities, gender neutral alongside single sex spaces, is likely to be optimal.

5.      Document what considerations have informed your approach/any changes made to facilities.

6.      Take legal advice on specific issues arising from your workplace/employee population.

For specific and tailored advice, please get in touch with Eliza Nash or your usual contact at Constantine Law.