Supreme Court judgment on the meaning of "sex" in the Equality Act 2010: For Women Scotland

On 16 April 2025 the Supreme Court handed down judgment in For Women Scotland v The Scottish Ministers. The case concerned how the terms “man”, “woman” and “sex” should be interpreted in the Equality Act 2010 (EA 2010) in light of the Gender Recognition Act 2004 (GRA).

The Supreme Court has published a short press summary of the judgment.

The Gender Recognition Act 2004 and the Equality Act 2010

The GRA enables people whose gender identity does not correspond with the sex originally registered on their birth certificate (trans people) to obtain a gender recognition certificate (GRC); this provides legal recognition in their acquired gender.

Gender recognition certificates

Section 9(1) of the GRA provides that legal recognition of the person’s acquired gender changes their sex “for all purposes” to correspond with that gender (“sex” and “gender” are used interchangeably in the GRA and elsewhere in legislation). Therefore, once in possession of a GRC, someone who was registered as male at birth would become a woman as a matter of law, or vice versa, under the GRA. The sex recorded on their birth certificate would be amended to reflect this. The acquired gender can only be man or woman.

The legal recognition granted to GRC holders is limited by section 9(3) of the GRA in various areas. For instance, in relation to peerages, succession, parental status regarding children, and certain gender-specific offences. In these circumstances, a GRC holder may lawfully be treated according to their sex registered at birth. The GRA also specifies that section 9(1) is subject to provisions in other legislation. That is to say, a GRC will not modify legal sex if that would contradict the provisions of any other primary or secondary legislation.

Equality Act provisions regarding gender reassignment and sex

The EA 2010 prohibits direct and indirect discrimination, harassment and victimisation on the basis of ‘protected characteristics’ in various circumstances. There are nine protected characteristics, including gender reassignment and sex.

It applies 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 protects men and women from discrimination in various circumstances on the basis of the protected characteristic of sex.

There are a number of exceptions to the prohibition on discrimination. For example, provisions on pregnancy and maternity discrimination permit differential treatment on the basis of sex which might otherwise be direct discrimination.

Separate and single-sex services, such as women-only counselling services, may also be permitted, where their provision is a proportionate means of achieving a legitimate aim.

For the purposes of the EA 2010, a man is defined as a “male of any age” and a woman as a “female of any age”. Those definitions do not state expressly whether “sex” in the act means biological sex (defined by the Supreme Court as “the sex of a person at birth”).

Interaction between the GRA and the EA

There has been considerable debate about the GRA and its interaction with the definition of “sex” in the EA 2010. Specifically, whether a GRC changes a person’s sex for the purposes of the EA 2010: from their biological sex to the sex that corresponds with their acquired gender, referred to by the Supreme Court as “certificated sex”.

The Equality and Human Rights Commission (EHRC) issued guidance in 2011 which said service providers that provide single or separate sex services for women and men should treat trans people according to the gender in which they present (i.e., regardless of whether they have a GRC; para 13.57).

Further guidance on the provision of separate and single sex services published in 2022 said that, for the purposes of the EA 2010, a person’s legal sex is their biological sex recorded on their birth certificate, and that a trans person can change their legal sex by obtaining a GRC. It also said that providers of separate and single sex services could lawfully exclude trans people, whether or not they have a GRC, provided doing so was a proportionate means of achieving a legitimate aim.

The Scottish legal proceedings

The legal proceedings that led to the Supreme Court’s decision began in Scotland. The Gender Representation on Public Boards (Scotland) Act 2018 introduced an objective that 50% of non-executive members of public boards should be women. It defined “woman” as including people with the protected characteristic of gender reassignment, providing they are living as a woman and proposing to undergo, are undergoing, or have undergone a process to become female.

The campaign group For Women Scotland (FWS) successfully challenged this definition on the basis that it impinged on protected characteristics defined by the EA 2010 (PDF), which are reserved to the UK Parliament and therefore not within the devolved competence of the Scottish Parliament.

The Scottish Government then published revised guidance on the meaning of “woman” in the act, referring to the definition of “woman” in sections 11 and 212 of the EA 2010. It also said that, where a full GRC had been issued to a person, their sex would be the same as their acquired gender.

FWS brought a further challenge against this definition, arguing that a GRC does not alter a person’s sex for the purposes of the EA 2010.

The Outer House of Scotland’s Court of Session disagreed, concluding that “sex” is not limited to biological or birth sex, but includes those in possession of a GRC.

FWS were unsuccessful in their appeal to the Inner House of the Court of Session (PDF), which found that the guidance did not conflate two separate protected characteristics. The court said that a person with a GRC in their acquired gender possesses the protected characteristic of gender reassignment. Separately, for the purposes of sex discrimination, they also possess the protected characteristic of sex according to the terms of their GRC.

Supreme Court judgment

FWS appealed against this decision to the Supreme Court, which unanimously concluded that references in the EA 2010 to “man”, “woman” and “sex” were references to biological sex (meaning “the sex of a person at birth”). The judgment has not changed the law. It has given an authoritative interpretation of the legislation as enacted.

A number of organisations were permitted to make submissions as third party interveners in the case: Amnesty International; the Equality and Human Rights Commission; Sex Matters; and a joint submission from Scottish Lesbians, the Lesbian Project and LGB Alliance. Their evidence is discussed in the judgment at paragraphs 31-35.

The Supreme Court can grant permission to third party interveners where it would help the court in its determination by providing relevant legal arguments that would not be covered by one of the existing parties.

Process of interpreting the Equality Act to determine Parliament’s intention

The court decided that the general rule that the sex of a person with a GRC was their acquired sex would apply unless an exception was required or needed by the language of the EA 2010. The court therefore undertook a careful analysis of the act’s provisions to decide whether they indicated that a biological sex interpretation was needed. This involved considering whether the “terms, context and purpose” of the EA 2010 are such that its provisions would be rendered incoherent or unworkable by adopting a certificated definition of sex.

In doing so, the court applied well established rules of statutory interpretation to determine what Parliament had intended when enacting the EA 2010. The court noted that its role was limited to this, and it was not seeking to determine arguments in the public domain on issues of sex and gender:

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. It has a more limited role which does not involve making policy. The principal question which the court addresses on this appeal is the meaning of the words which Parliament has used in the EA 2010 in legislating to protect women and members of the trans community against discrimination. Our task is to see if those words can bear a coherent and predictable meaning within the EA 2010 consistently with the Gender Recognition Act 2004 (“the GRA 2004”). (Para 2)

Supreme Court’s reasoning and findings

The court said that the EA 2010 seeks to reduce inequality and to protect people with protected characteristics against discrimination. The act recognises women as having the protected characteristic of sex and “transsexual” people (the term used in the act) as having the protected characteristic of gender reassignment.

The court found that as a matter of ordinary language, the provisions relating to sex discrimination could only be interpreted as referring to biological sex. For example, the provisions relating to pregnancy and maternity are based on the fact that only biological women can become pregnant.

It also found that a certificated sex interpretation would cause confusion and impracticability in relation to other parts of the EA 2010, such as the provision of single and separate sex services, and could undermine the protection given to those with the protected characteristic of sexual orientation.

Overall it concluded that any interpretation other than one based on biological sex would render the EA 2010 incoherent and impracticable to operate. Therefore, the guidance issued by the Scottish Ministers, which FWS was challenging, was incorrect.

Implications for the interpretation of other legislation and the rights of trans people

The court noted that the GRA continues to have relevance and importance in providing for the legal recognition of transgender rights, and that this has practical effects in the context of marriage, pensions, retirement and social security. It said that when interpreting references to men and women in other legislation, whether enacted before or after the GRA, careful consideration would need to be given to the wording, context and policy of the statute in question to determine whether a biological or certificated definition was intended.

The court also concluded that a biological sex interpretation would not have the effect of disadvantaging or removing protections from trans people. This is because, in addition to protection based on the protected characteristic of gender reassignment, they would also be protected from discrimination based on being perceived as or associated with a sex which differed from their biological sex (paras 249-261).

Changing the definition

No further appeal against the decision is possible in the UK courts. It has been 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.

Any change to the definition of sex for the purpose of the EA 2010 would require legislation to be passed by Parliament.

Government response

Bridget Phillipson, Minister for Women and Equalities, made a statement in the Commons on 22 April. She said that the ruling had brought welcome clarity and confidence for women and service providers. However, she said that there is a need to ensure that the implications of the judgment are clear across a range of settings, including healthcare, prisons and sport.

She also said that the EHRC, as Britain’s equality regulator, was working quickly to issue an updated statutory code of practice to reflect the judgment. She expects the EHRC to engage with a range of stakeholders with different views in the development of the code of practice and the guidance.

Further guidance will also be produced by a range of other organisations, such as the NHS.

Equality and Human Rights Commission guidance

The EHRC issued an interim update on 24 April. It has now been withdrawn.

The update noted that the judgment has implications for many organisations, including workplaces, services open to the public, sporting bodies, schools and associations.

It said the EHRC aimed to provide an updated code of practice to the government by the end of June for ministerial approval, following a two-week consultation period beginning in May 2025.

Single-sex toilets and other facilities

The update said that it is compulsory for workplaces to have sufficient single-sex toilets, as well as changing and washing facilities where needed. This purported to reflect the Workplace (Health, Safety and Welfare) Regulations 1992, which require separate toilets for men and women unless single lockable rooms can be provided. These regulations were not considered in the FWS judgment.

The update was subsequently amended to note the application of these regulations to workplaces. It said

These require suitable and sufficient facilities to be provided including toilets and sometimes changing facilities and showers. Toilets, showers and changing facilities may be mixed-sex where they are in a separate room lockable from the inside. Where changing facilities are required under the regulations, and where it is necessary for reasons of propriety, there must be separate facilities for men and women or separate use of those facilities such as separate lockable rooms.

It also said that it is not compulsory for services which are open to the public to be provided on a single-sex basis, or to have single-sex facilities such as toilets, but that this is permitted if it is a proportionate means of achieving a legitimate aim, and meets other conditions in the act. However, not providing single-sex services or facilities could be indirect discrimination against women.

The interim update said that people should not use facilities provided for the other biological sex “as this will mean they are no longer single-sex facilities and must be open to all users of the opposite sex”. Further, it said there may be circumstances where trans people are not permitted to use single-sex facilities according to their acquired gender or their biological sex, and that in these cases they should not be put in a position where there are no facilities for them to use. It recommended that where possible, mixed-sex facilities should be provided in addition to single-sex facilities.

Response from parliamentary committees

The Chairs of both the Joint Committee on Human Rights (JCHR) and the Women and Equalities Committee (WEC) wrote to the EHRC, expressing some concerns about the approach taken.

Lord Alton, Chair of the JCHR, addressed a series of questions to the then Chair of the EHRC, Baroness Falkner. These included the sufficiency of the proposed two-week consultation, the legal status of the interim guidance, and the failure of the guidance to address the Supreme Court’s conclusions about the rights of trans people.

Sarah Owen MP (Lab), Chair of WEC, wrote in similar terms, questioning the consultation period and how the new code of practice would support the rights of all people in line with the Supreme Court judgment.

In light of these representations and the level of public interest, the EHRC published an update on 14 May setting out further details of the consultation process. It said it would run from 19 May to 30 June, rather than for two weeks as originally proposed.

The consultation was published on 20 May. It closed on 30 June 2025. It focused on sections of the code of practice that require updating following the judgment. While the consultation was running, the EHRC held Q&A sessions with stakeholders representing affected protected characteristic groups.

Legal challenge

The Good Law Project and a number of individual claimants subsequently brought judicial review proceedings against the EHRC challenging the legality of the interim update on the basis that the content was legally inaccurate, among other things.

In February 2026, the High Court held that the interim update was not inaccurate and the application for judicial review was dismissed (PDF). It also held that the Good Law Project did not have standing to bring the challenge because it was not personally or directly affected by the decision.

The EHRC issued a statement welcoming the decision. The Good Law Project said that three of the claimants had applied for permission to appeal.

Next steps

A draft code of practice was submitted to the government on 4 September 2025.

The government is currently considering the draft code. If it is approved it will be laid before Parliament for a period of 40 days. The draft code will then be subject to the negative resolution procedure. If neither House passes a resolution disapproving the draft within 40 days, the EHRC may issue the code in draft. The code will then come into force in accordance with an order made by the secretary of state.

On 14 April 2026 the government said in a written ministerial statement that it had received an updated draft from the EHRC on 13 April, following engagement and further legal analysis. It said that it was not possible to make any further announcement during the pre-election period for the devolved administrations, given that it would apply across the UK. However, it said the government is taking urgent action to meet its intention of laying the draft code before Parliament for scrutiny in May, and as soon as practicable after the election period.