29/04/2025

Supreme Court defines ‘Woman’ for purposes of Equality Act 2010 as a biological female

On 16 April 2025 the UK Supreme Court (SC) issued a unanimous decision that clarifies the legal definition of a woman under the Equality Act 2010 (EA). The landmark decision determined that when a ‘woman’ is referred to in the EA it refers strictly to a biological female. In doing so the SC rejected an interpretation that ‘woman’ includes a transgender woman with a Gender Recognition Certificate (GRC).

Background

The Gender Recognition Act 2004 (GRA) is a UK wide law that applies in Northern Ireland and allows transgender persons to legally change their gender. Under the GRA, a person can apply for a GRC which legally recognises their acquired gender and enables them to update official documents such as their birth certificate. To apply for a GRC a person must provide evidence of gender dysphoria, live in their acquired gender for at least two years, and make a statutory declaration of intent to live permanently in that gender.

The case before the SC originated from a decision taken by the Scottish Government that, when aiming to increase female representation on public sector boards, the definition of a ‘woman’ would include transgender women with a GRC. For Women Scotland, a women’s rights group, argued that the definition of woman should be limited to those born biologically female; they unsuccessfully challenged the Scottish Government’s decision in two lower courts, and the SC decision has therefore had the final say on the matter.

 The Supreme Court Judgment

There has been a lot of commentary since the decision was handed down, and it is important to remember that the SC’s task was to determine the definition of a ‘woman’ when applying and interpreting the EA. The decision focuses on statutory interpretation and is not a personal opinion or social commentary on transgender status.

The SC handed down an 88-page judgment that is highly detailed and technical and that ultimately finds that a ‘woman’ under the EA 20 refers exclusively to biological females.

In summary the SC’s reasoning focused on the following points:

1. Clarity in law and rejecting ‘variable’ definitions – legal definitions must be coherent and consistently applied; the SC stated sex-based language must be interpreted consistently throughout the EA. However if the definition of ‘woman’ was wider than a biological female different definitions of ‘woman’ would have to be applied depending on what section of the EA was being considered to ensure the legislation continued to operate effectively in practice;
2. Biological basis of pregnancy and maternity – terms related to pregnancy and maternity protections can only apply to biological females;
3. Avoiding two-tiered protection – a system whereby only those trans persons with a GRC receive enhanced protections would be deemed unworkable and create a sub-group of trans persons i.e. those with a GRC having enhanced rights compared to those trans persons without a GRC.
4. Existing protections for transgender people – the judgment affirmed that transgender individuals already receive protection under the protected characteristic of gender reassignment. Trans individuals, regardless of GRC status, remain protected against discrimination and harassment and they can also still claim sex-based discrimination on the basis that they are perceived as female.

Implications and Commentary

The decision has far-reaching consequences for gender definitions within UK equality law. It impacts policy, public services and workplace protections, and is already sparking significant debate across legal, political, and social spheres. Whilst some will welcome the clarity, others will express concern about the impact on transgender inclusion.

The EA does not apply in Northern Ireland where sex discrimination laws are governed by the Sex Discrimination (Northern Ireland) Order 1976 and the Sex Discrimination (Gender Reassignment) Regulations (Northern Ireland) 1999. Furthermore, the definition of ‘gender reassignment’ differs in Northern Ireland compared to GB as our Regulations require individuals to be transitioning under medical supervision to qualify for protection. Despite these differences, as the GRA applies in Northern Ireland and the Sex Discrimination Order reflects the precursor to the EA in GB, we strongly expect that biological sex will similarly be recognised in Northern Ireland law and the Courts and Tribunals in this jurisdiction will apply the SC decision.

Interim guidance

On 25 April 2025, the Equality and Human Rights Commission (EHRC) released interim guidance to address the practical implications of the UK Supreme Court judgment in the case of For Women Scotland v The Scottish Ministers. This update offers information for employers across the UK navigating changes in equality legislation whilst awaiting the updated guidance and Code.

The EHRC plans to submit an updated Code of Practice to the UK Government by the end of June 2025 for ministerial approval. To inform this update a public consultation will run in mid-May 2025 for two weeks, focusing solely on the practical implications of the SC decision rather than its legal interpretation.

In NI the Equality Commission has also stated that it intends to publish new formal guidance in June 2025 and has advised they will also conduct a short consultation with interested parties beforehand. The Equality Commission has indicated that their initial view is that the judgment is likely to be deemed by our industrial tribunals and courts to be highly persuasive and, consequently, it is likely to be followed by the industrial tribunals and courts here when they are considering cases where similar issues arise, e.g. cases of alleged sex or gender reassignment discrimination contrary to the SDO.

Preparing for compliance: Employer Actions

Until the updated guidance is issued, we recommend employers take the following steps:

1. Facility provision:

Under separate Workplace Health, Safety and Welfare legislation, employers are required to provide sufficient single-sex toilets and single-sex washing/changing facilities where needed. Broadly speaking, these must be separated by sex except where they are contained in separate lockable rooms.

The SC decision has clarified that sex means biological sex, therefore (subject to any forthcoming guidance) the logical application of the decision is that only biological women are permitted to use the female facilities, and only biological men are permitted to use the male facilities; trans persons will be required to use the facilities of their birth sex and not their acquired gender.

Currently there is no legal obligation on employers to provide gender neutral facilities but there are calls for such spaces to be provided where possible.

It is currently the case that it is inappropriate to require transgender people to use the disabled facilities as these are for disabled persons. Updated and clear guidance on facility provision will be important for employers.

2. Policy review: ensure workplace policies refer to biological sex and gender reassignment accurately (rather than just gender);

3. Education and staff training: the SC decision does not mean that trans persons lose protections in the workplace; trans people continue to be protected from unlawful discrimination and harassment.

The SC decision undoubtedly generates strong opinions from/on behalf of the trans community and also from/on behalf of those who hold gender critical beliefs. Both are protected groups under our equality legislation (transgender status and philosophical belief respectively). Managers should be alert and responsive to any provocative and disrespectful behaviours. Employees should also understand that no protected group has overriding rights over others and training on dignity at work should be provided or updated as necessary;

4. Data Collection: Differentiate between biological sex and trans identity in demographic reporting.