Supreme Court decides that legal definition of “woman” refers to biological sex

Legal issues

Gender Recognition Act 2024

A person who is aged at least 18 can apply for a Gender Recognition Certificate (“GRC”) under the Gender Recognition Act 2024 (“GRA 2024”). This means that when a GRC is issued the person’s gender becomes “for all purposes” the acquired gender. Accordingly, if the acquired gender is the female gender, the person’s sex becomes that of a woman. There are however, some limitations to this provision.

Equality Act 2010

The Equality Act 2010 (“EA 2010”) protects people with “protected characteristics” against discrimination and harassment and prevents unfair treatment when accessing services. There are nine protected characteristics and the two relevant to the Supreme Court appeal were “sex” and “gender reassignment”. In the EA 2010:

• The protected characteristic of sex refers to a man or a woman which means a male or female of any age. The concept of sex is binary, a person is either a man or a woman. However, the word “biological” does not appear in the definition.
• The protected characteristic of gender reassignment is where a person is proposing to undergo, is undergoing or has undergone a process (or part of a process) for the purpose of reassigning the person’s sex by changing physiological or other attributes of sex. A transsexual person has the protected characteristic of gender reassignment. The definition does not depend on having a GRC.

The EA 2010 gives separate protection from discrimination, harassment and inequality to each of these two protected characteristics.

Supreme Court

The appeal related specifically to establishing the correct interpretation of the words used in the EA 2010 to protect women and members of the trans community against discrimination. The central issue was whether references in the EA 2010 to a person’s “sex” and to “woman” and “female” are to include persons who have an acquired gender through the possession of a GRC.

As the Supreme Court stated, the focus of the appeal was not on the status of the large majority of trans people who do not possess a GRC (whose sex in law remains their biological sex). The appeal addressed the position of the small minority of trans people with a GRC. According to the Office of National Statistics and based on the most recent data, there are 48,000 trans men and 48,000 trans women in England and Wales, and 19,990 in Scotland compared with a total of 8,464 people who have a GRC as at June 2024.

So, does the EA 2010 treat a trans woman with a GRC as a woman for all purposes within the scope of the EA 2010 or does “woman” and “sex” in the EA 2010 refer to a biological woman and biological sex?

The terms “biological sex” and “certificated sex” do not appear anywhere in the EA 2010 and the Supreme Court took the following approach:

• It considered the core provisions in the EA 2010 relating to “sex” to establish “whether as a matter of ordinary language these provisions can only properly be interpreted as meaning biological sex, or whether they are to be interpreted as also extending to include persons living in the opposite acquired gender who have been issued with a GRC.”
• It then considered the practicability and workability of the EA 2010 duties and protections if a “certificated sex” interpretation was adopted.

The Supreme Court found that if a certificated sex interpretation was adopted this would lead to incoherence in the practical operation of the EA 2010. It said that “clarity and consistency about how to identify the relevant groups that shared protected characteristics were essential” to the practical operation of the EA 2010.

In a lengthy judgment the Supreme Court found that:

• Parliament intended that the words “man” and “woman” in the Sex Discrimination Act 1975 referred to biological sex.
• The Gender Recognition Act 2004 did not make any express amendments to the definition of “man” and “woman” set out in the 1975 Act.
• There was no reason to suppose that Parliament intended to change the meaning of “sex” in the EA 2010 from that in the 1975 Act.
• The words “sex”, “man” and “woman” in the EA 2010 have their biological meaning (and not a certificated sex meaning) because the protections relating to pregnancy and maternity discrimination and the references to breastfeeding and risks to pregnant women are predicated on the fact of pregnancy or giving birth and only biological women can become pregnant.
• Trans people have the protected characteristic of gender reassignment.
• Gender reassignment and sex are separate bases for discrimination and inequality. The Scottish Ministers’ approach would, within the same protected characteristic of gender reassignment, give trans people with a GRC more rights than those without a GRC.
• There are other provisions whose proper functioning requires a biological interpretation of “sex”. These include separate spaces, single sex services (such as changing rooms and medical services), single sex associations and women’s fair participation in sport.
• In relation to the public sector equality duty (PSED), it would be impractical to apply a certificated sex approach. For instance, in relation to an organisation’s positive action provisions, would the organisation have to include trans women with GRCs (but not those without) and exclude biological females with GRCs?
• The EHRC had already advised the Government back in 2023 that there would be greater legal clarity in eight areas if sex is defined as biological sex in the EA 2010. Those areas were pregnancy and maternity, freedom of association for lesbians and gay men, freedom of association for women and men, positive action, occupational requirements, single sex and separate sex services, sport and data collection.

The definition of “sex” in the EA 2010 is binary, a person was either a woman or a man. The Supreme Court unanimously held that the meaning of the words “sex”, “man” and “woman” is biological. Interpreting “sex” in the EA 2010 as certificated sex would cut across the definitions of “man” and “woman” and “sex” in an incoherent way and “would render the EA 2010 incoherent and impracticable to operate.” The words “sex” and “woman” appear across different parts of the EA 2010 and it would be “surprising if they were intended to have different meanings”.

Accordingly, the guidance issued by the Scottish Ministers was incorrect and a person with a GRC in the female gender does not come within the definition of “woman” for the purposes of the EA 2010.

Crucially, the Supreme Court stressed that the biological interpretation of “sex” would not disadvantage or remove important protections under the EA 2010 from transgender people. They would still be protected from discrimination through the protected characteristic of gender reassignment and would also be protected from discrimination and harassment in their acquired gender.

Implications

There is no doubt that the decision has significant implications for employers, service providers, sporting bodies and schools. Shortly after the judgment, the EHRC published an interim update to highlight the main consequences. For workplaces and services open to the public, the EHRC advises that:

• Trans women should not be permitted to use the women’s facilities and trans men should not be permitted to use the men’s facilities. Otherwise, they are no longer single-sex facilities and must be open to all users of the opposite sex.
• Where facilities are available to both men and women, trans people should not be put in a position where there are no facilities for them to use.
• Where possible, mixed-sex toilet, washing or changing facilities, in addition to sufficient single-sex facilities, should be provided.
• Where toilet, washing or changing facilities are in lockable rooms (not cubicles) which are intended for the use of one person at a time, they can be used by either women or men.

More details can be found in the interim update EHRC Interim update.

The EHRC is working on more comprehensive guidance and will publish a revised Code of Practice for services, public functions and associations to reflect the practical implications of the Supreme Court decision. Originally, it said that there would be a two-week consultation exercise on this from mid-May and the revised Code of Practice would be provided to the Government in June. However, the EHRC has just announced that the consultation period has been extended. It will be launched on 19 May 2025 and close on 30 June 2025. The consultation will focus on sections of the Code of Practice that need updating following the Supreme Court’s decision.

Many employers will probably wait until the revised Code of Practice is published before reviewing their policies and procedures.

The implications of the decision are far-reaching and the matter will remain high-profile, especially when the revised Code of Practice is published.