In April, the UK Supreme Court ruled that use of the word “woman” in the Equality Act 2010 refers to people whose biological sex is female. This article sets out the context for that legal case, summary findings from the case itself, and looks at how this ruling may – or may not – affect things here in NI.

[UPDATE 10/9/25: Since this article was published in June 2025, the Equality Commission for Northern Ireland has sought legal clarity from the Belfast High Court amid “significant” uncertainty over the ruling’s effect in Northern Ireland, with formal guidance still pending.”. We have provided additional information in the final section of this article to reflect this development.]

The Supreme Court’s determination centres on interpretation of the word “woman” in parts of the Equality Act that do not apply in Northern Ireland. However, that does not mean that there will be no consequences here.

The Equality Commission has indicated that it plans to produce guidance on the ruling later this month. However, even when that happens it will not necessarily be the end of the story.

In fact, there could be years of legal arguments that follow this ruling – both on interpretations of the consequences of the ruling and, potentially, challenges to the ruling itself.

  • The Ruling

On 16th April 2025, in the case For Women Scotland Ltd. v The Scottish Ministers, the UK Supreme Court made a determination on the meaning of the word “woman” in the Equality Act (EA) 2010 as applied in Scotland in the Gender Representation on Public Boards (Scotland) Act 2018.

The Court ruled that those who drafted the EA 2010 intended “woman” to mean “biological woman”, in other words, that “woman” is a sex assigned at birth. The ruling states in point 2, however, that it only relates to interpretation of the EA 2010, and that:

“It is not the role of the court to adjudicate on the arguments in the public domain on the meaning of gender or sex, nor is it to define the meaning of the word “woman” other than when it is used in the provisions of the EA 2010.”

  • Equality Act

The Equality Act 2010 (EA) provides a consolidated legal framework to protect people against discrimination and harassment on the grounds of nine protected characteristics: age, disability, gender reassignment, marriage and civil partnership, pregnancy and maternity, race, religion or belief, sex and sexual orientation.

It applies in England, Scotland and Wales in various scenarios “including at work, in education, in relation to the provision of services and public functions, and to membership of clubs and associations.”

The Act defines “sex” as being a “man or a woman”. The Act defines a “man” as a “male of any age” and a “woman” as a “female of any age”. It does not specifically link these definitions to sex assigned at birth.

  • Gender Recognition Act

The Equality Act 2010 built on the earlier Gender Recognition Act (GRA) 2004, which enables people whose gender identity does not correspond with the sex assigned at birth to obtain a gender recognition certificate (GRC).

To apply for a GRC, someone must usually have a diagnosis of gender dysphoria, must live in their “acquired” gender for at least two years and make a legal declaration that they intend to live permanently in that gender. A fresh birth certificate is created to reflect GRCs, which means that legally, a person’s sex is changed to correspond with their gender.

In the Republic of Ireland, the Oireachtas passed a Gender Recognition Act 2015 which allows Irish citizens to legally change their gender based on self-identification. But this approach has not been taken in the UK.

  • Background to the Supreme Court case

In 2018, the Gender Representation on Public Boards (Scotland) Act introduced an objective that 50% of the non-executive members of public boards in Scotland should be women. Section 2 of the Act included trans women, whether or not they had a GRC, using these words:

“”[w]oman” includes a person who has the protected characteristic of gender reassignment (within the meaning of section 7 of the Equality Act 2010) if, and only if, the person is living as a woman and is proposing to undergo, is undergoing or has undergone a process (or part of a process) for the purpose of becoming female.”

A succession of legal challenges to the Act were mounted over subsequent years by the campaign group For Women Scotland Ltd (FWS), who argued that the Scottish government’s definition of a “woman” in the 2018 Act was too inclusive, that it conflicted with the definition of a “woman” in the Equality Act 2010 and that Westminster law (EA 2010) took precedence over Scottish law in these matters.

FWS’s first case was unsuccessful, Lady Wise ruling on 23 March 2021 that the Scottish Government had acted lawfully by including trans women as women.

FWS’s second case at Second Division of the Inner Court was successful. The Scottish Parliament Information Centre explains:

“[The] Scottish Government could have lawfully added the protected characteristic of gender reassignment, which would have included trans men and trans women. But it created a new protected characteristic of trans women, and the Scottish Parliament cannot modify protected characteristics in the Equality Act.”

In other words, the 2018 Act had used the wrong words. “Gender reassignment” would have reflected the language in the EA 2010. But attaching the word “woman” to this, in the manner cited above, was extending the EA 2010 in a way that the Scottish Parliament did not have the authority to do.

This led the Scottish government to tighten the language in their guidance, now pointing to “gender reassignment” as a protected category, and specifying that for a person with a full GRC, their sex would be the same as the gender on their GRC.

FWS then took the case to the Outer House of Scotland’s Court of Session. They were unsuccessful, the Court concluding that “sex” is not assigned at birth and includes people with a GRC. FWS appealed this decision in the Inner House of the Court of Session, which was also unsuccessful.

  • Supreme Court

This brings us to the 2025 UK Supreme Court ruling. This ruling was different to previous judgements, which had been about the technical use of specific language and the need to stick to the terminology of EA 2010. The UK Supreme Court ruling, however, sought to interpret what the original language of EA 2010 actually meant.

The UK Supreme Court ruled that for the purposes of the Equality Act 2010, sex is to be defined as “biological sex”. The ruling states that the EA 2010 was intended to update the Sex Discrimination Act (SDA) 1975. It says there is “no doubt” that the Parliamentary debates leading to the SDA 1975 intended the words “man” and “woman” to refer to biological sex.

Another factor that underpins the UK Supreme Court ruling is the EA 2010’s provisions on pregnancy and maternity, which states that only biological women can become pregnant. The Court ruled this provision is “unworkable unless “man” and “woman” have a biological meaning”.

Finally, the UK Supreme Court ruling states that the EA 2010 must be “predictable” and “consistently understood” in a way that can be “applied in practice”.  Examples given include changing rooms, medical services, single sex higher education institutions, single sex characteristic associations and charities, sport, equal pay and the armed forces.

Many of these could appear to contradict the GRA 2004, which was broadly understood to mean that once a person received a GRC their “acquired” gender would correspond with their sex “for all purposes” – i.e. a trans woman with a GRC is legally a woman. The GRA, however, also notes that “for all purposes” is subject to “any other enactment or any subordinate legislation”.

The Supreme Court noted that the GRA 2004 continues to be important in providing legal recognition for trans people’s rights. It further noted that “gender reassignment” was a protected category under the EA 2010. The Supreme Court declined to hear evidence from any trans people.

No further appeal against the decision is possible in the UK courts. However, an Act of the UK Parliament could clarify or change it. In April 2025, there were media reports that the Supreme Court decision is to be challenged in the European Court of Human Rights.

  • After the ruling

Great Britain’s Equality and Human Rights Commission (EHRC) provided an interim update on 25 April 2025, underlining that “sex” means “biological sex” in EA 2010, regardless of whether someone has a GRC.

The update said that this is likely to affect workplaces, services that are open to the public, sporting bodies, schools and associations. It stated that trans people should not now be allowed to use single-sex facilities that align with their gender identities, and in some cases, should not be allowed to use facilities that align with their sex assigned at birth.

  • Reaction in Northern Ireland

A range of public bodies in Northern Ireland reacted quickly to the Supreme Court ruling. Fermanagh and Omagh District Council said they would be “developing new guidance for the use of changing rooms at leisure facilities and toilets” (they later apologised for any hurt caused). It’s worth noting that, in general, when a public body is considering a policy change that could have an “adverse impact” on any group it is required to carry out an Equality Impact Assessment (EQIA).

Councillors on Armagh City, Banbridge and Craigavon Borough Council proposed that Lurgan Pride should not finish in a public park in case trans people had to use the toilet, citing the UK Supreme Court ruling as the reason – although a decision is paused on equality grounds.

On 29 May 2025, the News Letter reported that Causeway Coast and Glens Borough Council had already begun to enforce a single-sex toilet and changing policy with trans women not permitted to use the,what was termed, “female facilities”. 

The Irish Football Association indicated that they would review the judgement and take necessary steps “to fulfil our obligations under the Equality Act 2010, as clarified by this ruling.” DUP MLA Carla Lockhart said that this was “a logical and sensible step”.

The BBC reported that Paul Givan, DUP Minister for Education, “asked officials to ensure that his department is complying with the Supreme Court’s ruling that a woman is defined by biological sex.”

The Northern Ireland Assembly debated the implications of the Supreme Court ruling on 28 April 2025. DUP MLA Jonathan Buckley welcomed the ruling as a “moment of truth”, criticising other parties for promoting a “warped and dangerous ideology” on gender issues.

First Minister, Michelle O’Neill, stated that the Executive Office had sought advice from officials and was awaiting guidance from the Equality Commission [of Northern Ireland], and stressed the need to “demonstrate some compassion” towards the LGBTQ+ community.

The following day in the Assembly, People Before Profit’s Gerry Carroll said that the ruling had become “a lightning rod” for attacks against trans people, highlighting the fear and anxiety it has caused.

TUV MLA Timothy Gaston asked each Northern Ireland Assembly department (28/04/25 – 30/04/25) to clarify how they will respond to the Supreme Court ruling. Most government departments replied that they will wait for the specific guidance of the Equality Commission of Northern Ireland.

The Equality Commission of Northern Ireland issued a statement on 17 April 2025 to say that they would be reviewing the findings of the UK Supreme Court ruling “at pace” in order to provide specific guidance for Northern Ireland. It aims to report in June 2025.

  • Equality legislation in Northern Ireland

As a result of partition and the conflict, there is a very specific patchwork of equality legislation in Northern Ireland that is quite different to the wider UK, where equality legislation was consolidated by the EA. In fact, on 10 June 2024, the Executive Office Committee at Stormont launched an Inquiry into Gaps in Equality Legislation precisely because the Equality Act 2010 does not apply in Northern Ireland.

There may be different equality protections in relation to sex, gender and GRCs, when comparing NI and GB. Equality protections may be available in GB that are not available in NI, and vice versa. The Equality Commission for Northern Ireland laid out the differences between GB and NI in detail in a recent report, as has an Assembly briefing paper. 

A variety of domestic legislation may be relevant to the Supreme Court ruling in Northern Ireland. This includes:

None of these pieces of legislation mention “biological sex” although this may have been assumed at the time of writing. Other legislative considerations could include the various EU (Withdrawal Agreement) Acts that provide for non-diminuation of rights following Brexit.

The Sex Discrimination (Gender Reassignment) Regulations (Northern Ireland) 1999 added an amendment to the Sex Discrimination (Northern Ireland) Order 1976: Article 4A, which includes protections for people who intend to undergo, are undergoing, or have undergone gender reassignment.

However, there are exceptions where “being a man is a genuine occupational qualification for the job” and the same for a woman. So the notion of “biological” sex may be implied.

The legislative landscape changed for trans people in the UK with the Gender Recognition Act 2004. This is a UK wide law that applies in Northern Ireland. People in Northern Ireland can apply for GRCs. 

  • Does the Supreme Court ruling apply in Northern Ireland?

The Supreme Court’s ruling centres on the meaning of the word “woman” in the Equality Act 2010 – an Act that largely does not apply in Northern Ireland.

It might seem, therefore, that the ruling has no effect in Northern Ireland. However, things are more complicated than that.

As noted previously, the Equality Commission of Northern Ireland is due to report in June 2025. In a press statement, it stated that their “initial view” was that the UK Supreme Court ruling may be “highly persuasive” in industrial tribunals and court cases in Northern Ireland.

In the meantime, however, we can point to various factors which will impact on the Supreme Court ruling’s applicability to Northern Ireland.

First of all, the Gender Recognition Act 2004 applies in Northern Ireland. This may be a significant factor in working out the implications of the ruling locally, especially when the Equality Act 2010 does not apply in Northern Ireland (see below).

The UK Supreme Court does have jurisdiction in Northern Ireland. It is the court of final appeal for civil cases throughout the UK, including Northern Ireland.

However, the Supreme Court 2025 ruling was limited specifically to the Equality Act 2010. Only four provisions of  the Equality Act 2010 apply in Northern Ireland, none of which relate to this case. Outside of this, equal opportunities and discrimination are transferred matters under the Northern Ireland Act 1998.

Legal academics, Deb, de Mars, Murray and O’Donoghue have argued that because the UK Supreme Court made clear that it was not making general definitions about sex and gender outside of the Equality Act 2010, that it follows that the term “woman” should continue to be understood as it has been to date in Northern Ireland. Deb et al go on to argue that the fact that the Equality Commission for Northern Ireland has committed to reviewing its guidance is “particularly concerning, given that a judgment about the Equality Act 2010 does not apply to any employers, service providers or public bodies in Northern Ireland.”

Media reports have also suggested that Lady Hale, former President of the Supreme Court, has said the court’s ruling has itself been “misinterpreted”.

Another factor is that the Windsor Framework makes EU discrimination laws applicable in Northern Ireland. Even if the Supreme Court ruling was to overrule Northern Ireland’s existing discrimination laws, many EU laws are applicable to NI via the Windsor Framework.

The Northern Ireland Human Rights Commission points out that Article 2 of the Windsor Framework provides specific protection against discrimination as enshrined in the six EU equality directives. A 2024 Assembly briefing paper states that under Annex 1 of Article 2 of the Windsor Framework means Northern Ireland equality laws must keep pace with any changes in EU equality law. The Equality Commission for Northern Ireland further outline (p70-71) the relevant EU legislation that applies to NI, via the Windsor Framework, regarding trans equality. 

UN experts have raised questions about the implications of the Supreme Court ruling for international human rights standards. On 22 May, 18 United Nations experts warned that the Supreme Court ruling “risks entrenching legal uncertainty and undermining the rights of transgender persons in all aspects of life.” They noted that “the UK has previously been found in violation of the European Convention on Human Rights for failing to provide adequate legal recognition for trans individuals, leading to the adoption of the Gender Recognition Act in 2004,” and stated that “without corrective changes to law and policy, the current ruling could lead to similar legal challenges being reopened.”

On 29 April, the BBC reported that a challenge may be brought at the European Court of Human Rights on the basis that the law is incompatible with the rights of trans people under the European Convention on Human Rights.

  • Conclusions (for now)

The Equality Commission plans to release guidance on the relevance of the Supreme Court ruling for Northern Ireland in June 2025. Many Northern Ireland government departments and agencies are waiting for this guidance before determining their own course of action.

It will be not be straightforward to untangle the applicability of the UK Supreme Court ruling for NI because there exist: i) tensions between the Equality Act 2010 and the Gender Recognition Act 2004; ii) lack of applicability of EA 2010 to Northern Ireland iii) human rights protections of Article 2 of the Windsor Framework and iv) possible conflict with international human rights law.

The implications of the ruling for Northern Ireland may not be fully clear until people bring fresh court cases to test the judgement. As such, it may be many years until we can truly answer the question of whether, and how, the UK Supreme Court ruling applies in Northern Ireland. 

[UPDATE 10/9/25: The Equality Commission released their “Legal paper and information: The meanings of “sex”, “men”, “women” and “gender reassignment” in equality and allied legislation in Northern Ireland and interim information for employers, service providers and public authorities”. They state that they “aim to publish final guidance for employers, service providers and public authorities on what they need to do to fulfil their legal obligations”. To achieve this the Commission is embarking on a programme of consultation which is part of the following six steps:

Step 1: Publish paper with issues, legal questions, and interim guidance.
Step 2: 12-week consultation with stakeholders.
Step 3: Send pre-action protocol (PAP) letters to regulators and interested parties.
Step 4: Apply to High Court for a ruling on definitions of “sex,” “men,” “women,” and “gender reassignment.”
Step 5: Draft guidance based on the Court’s decision.
Step 6: Consult on draft, then publish final guidance and update as needed.]