IN For Women Scotland Ltd. v The Scottish Ministers [2025] UKSC 16, [2025] 2 W.L.R. 879 (“FWS”), the United Kingdom Supreme Court (“UKSC”) held that the meaning of the words “sex”, “woman” and “man” in the Equality Act 2010 (“EA 2010”) is biological. The definition of “woman” and “man” in the EA 2010 does not include individuals who, by virtue of possessing a Gender Recognition Certificate (“GRC”), have an “acquired” male or female gender.

The case arose when the Scottish Ministers issued guidance about the meaning of the term “woman” in the Gender Representation on Public Boards (Scotland) Act 2018 (“2018 Act”). The 2018 Act permits positive action in the appointment of women to non-executive positions on the boards of certain statutory authorities. Although “equal opportunities” are generally a reserved matter under Schedule 5 to the Scotland Act 1998 (“1998 Act”), section L2 of Schedule 5 allows the Scottish Parliament to legislate for the inclusion of persons with protected characteristics on such boards.

Section 2 of the 2018 Act, as enacted, adopted, a broad definition of “woman” by including those persons with a gender reassignment characteristic, who were living as women and who had undergone, were undergoing or were proposing to undergo a process of becoming female. The Outer House of the Court of Session initially held that section 2 did fall within the legislative competence of the Scottish Parliament (For Women Scotland Ltd. v The Lord Advocate [2021] CSOH 31, (2021) S.L.T. 639). However, on appeal, the Inner House (For Women Scotland Ltd. v Lord Advocate [2022] CSIH 4, (2022) S.C. 150) ruled that the wide definition in section 2 exceeded the powers devolved under section L2. While the Scottish Parliament could legislate for positive action in appointing women to the non-executive posts, the broad understanding of “woman” in section 2 impinged upon the protected characteristics of “sex” and “gender reassignment” in the EA 2010 – a power that was still reserved to the Westminster Parliament.

In response to the judgment of the Inner House, the Scottish Ministers issued statutory guidance clarifying that, for the purposes of the 2018 Act, “woman” has the meaning of that term under section 11 and section 212(1) of the EA 2010. “Woman” also included individuals whose acquired gender is female by virtue of a GRC. The organisation, For Women Scotland, brought an action for judicial review against this new guidance. The Outer House ([2022] CSOH 90, (2023) S.C. 61) and the Second Division of the Inner House ([2023] CSIH 37, (2024) S.C. 117) upheld the lawfulness of the revised statutory guidance. For Women Scotland then petitioned the UKSC, which allowed their appeal.

The UKSC began its analysis by setting out the appropriate method of statutory interpretation to be applied (at [8]–[14]). Focusing on the key words used by Parliament, it was necessary to determine the meaning of those terms, having regard to their context, as well as the “wider context and purpose of the non-discrimination provisions in the EA 2010” (at [166]). External aids, such as Explanatory Notes, could help to resolve doubts about the meaning of specific terms. However, external indicators had a reduced role where a “clear and unambiguous” meaning of key terms was already apparent in the statute (at [11]). In FWS, although the Explanatory Notes had previously been considered as important in defining the status and position of trans people in the EA 2010, the UKSC consistently discounted their relevance for identifying the proper meaning of “sex”, “woman” and “man” (at [81], [104]). The Court also emphasised the importance of words having a consistent and invariable definition within a single statute and it rejected the notion that “sex” could have different meanings depending upon the context in which it arises in the EA 2010 (at [189]–[197]).

The UKSC recognised that section 9(1) of the Gender Recognition Act 2004 (“GRA 2004”) establishes a general right for trans people with a GRC to be treated as having their “acquired gender”. However, under section 9(3), the legal effects of a GRC can be disapplied by another provision of the GRA 2004 or by any other enactment or subordinate legislation. The UKSC concluded that section 9(3) does not require that an enactment explicitly oust the operation of section 9(1) of the GRA 2004 (at [157]); rather it suffices that there would be a “clear incompatibility” or the provisions of the enactment would be “rendered incoherent or unworkable” if the GRC applied (at [157]). The Court also held that section 9(3) can be triggered even where an enactment was introduced prior to the GRA 2004 (at [103]).

Having set out their analytic framework, the UKSC unanimously concluded that a “certificated” definition of “sex” in the EA 2010 would have incoherent consequences (at [264]). Therefore, the terms “sex”, “woman” and “man” in the legislation must have a “biological” meaning. In reaching that finding, the UKSC referred to numerous provisions of the EA 2010 which, according to the Court, would be unworkable if the terms “sex” or “woman” encompassed trans women with a GRC. These provisions included, but were not limited to, sections on pregnancy and maternity (at [177]–[188]), insurance (at [183]–[184]), associations (at [229]–[231]), single-sex services and communal accommodations (at [211]–[225]), protections for gay and lesbian people (at [206]–[208]), data collection and the public service equality duty (at [237]–[244]) and single-sex sports (at [232]–[236]).

Although these findings meant that trans people with a GRC could not be treated as having their “acquired” gender for the purposes of the EA 2010, the UKSC concluded that a biological definition of “sex” did not necessarily disadvantage trans individuals. Trans people, who fall within the scope of section 7(1) of the EA 2010, could still invoke the protected characteristic of “gender reassignment” and a trans individual could also bring a claim for discrimination or harassment motivated by a perception that they are a woman or a man (at [256]).

The judgment in FWS has given rise to considerable public and political commentary and it has already begun to shape both the types and outcomes of litigation coming before courts and tribunals in the UK (e.g. Haynes v Thomson [2025] EWCC 50; Lockwood v Cheshire and Wirral NHS (2401211/2024 and 2407178/2024) (E.T.); Peggie v Fife Health Board (4104864/2024) (E.T.). The remainder of this case note focuses on two aspects of the decision: incoherence and compatibility with the European Convention on Human Rights (“ECHR”).

In FWS, the UKSC usefully draws out certain anomalies and incoherencies that would arise if “sex”, “woman” and “man” in the EA 2010 have a “certificated” meaning. The Equality and Human Rights Commission had previously identified these problems in 2023, when it advised the UK Government to define “sex” expressly as “biological” within the statute (EHRC, “Letter to Minister for Women and Equalities […]”, available at https://www.equalityhumanrights.com/our-work/advising-parliament-and-governments/letter-minister-women-and-equalities-definition (last accessed 9 February 2026)).

Yet, the reasoning of the UKSC is notable for failing to equally consider whether and how incoherence arises if “sex” in the EA 2010 does not include trans people with a GRC. For example, while a purely “biological” reading of Schedules 3 and 23 protects providers who want to exclude trans women from their single-sex services and communal accommodations, that reading might also absolutely prohibit the provision of women-only services in a trans-inclusive manner. Where a provider does wish to permit trans women to use their services or communal accommodations, FWS implies that the provider could no longer rely upon the single-sex exemptions in the EA 2010; rather, they would have to make their services available to all persons irrespective of sex.

It is at least questionable, particularly having regard to the wider context and purpose of the legislation, whether Parliament could have intended the EA 2010 to operate in such a restrictive manner – effectively ousting the possibility for non-trans women to choose to share women-only services and communal accommodations with trans women. Indeed, at one point (at [221]), the UKSC even seems to suggest that, in specific circumstances, providers could lawfully exclude trans people from both male and female services – if the gender reassignment of an individual means that it is legitimate and proportionate to also deny that person entry into services, which are associated with the individual’s “biological” sex.

A second key question post-FWS is the status of the GRC in UK law and whether this satisfies the state’s obligations as a party to the ECHR. Under Article 8 of the Convention, the UK must provide a mechanism through which trans individuals can obtain legal gender recognition (“LGR”). Although the European Court of Human Rights (“ECtHR”) extends a (decreasing) margin of appreciation to countries when deciding how to acknowledge a change of legal sex (Goodwin v United Kingdom (2002) 35 E.H.R.R. 18; Y v Poland (Application no. 74131/14), Judgment of 17 February 2022, not yet reported), domestic LGR procedures must be “quick”, “transparent” and “accessible” (X v The Former Yugoslav Republic of Macedonia (Application no. 29683/16), Judgment of 17 January 2019, not yet reported, at [70]) and they must also be “clear and foreseeable” for applicants (X and Y v Romani (Application nos. 2145/16 and 20607/16), Judgment of 19 January 2021, not yet reported, at [179]).

To the extent that FWS now establishes the entire area covered by the EA 2010 as an exception to the operation of a GRC, there is doubt that the UK sufficiently complies with its obligations under the Convention. Given that ECHR, Article 8 is a qualified protection, the ECtHR would undoubtedly permit some restrictions on the operation of a GRC for the purposes of equalities law, particularly where the UK Government could argue that limitations are necessary to protect the rights and freedoms of women. Yet the absolute nature of the FWS reasoning – coupled with the UKSC’s observation that a similar application of section 9(3) may also oust the operation of a GRC in other areas of law, including the Human Fertilisation and Embryology Acts (at [105]–[108]) – calls into question the current, substantive availability of LGR in the UK.