Sex Equals Biological Sex

For the purposes of the Equality Act 2010, the definitions of ‘woman’, ‘man’ and ‘sex’ are by reference to biological sex

For Women Scotland Ltd v Scottish Ministers considers whether a person with a full Gender Recognition Certificate which recognises that their gender is female, is a “woman” for the purposes of the Equality Act 2010 (“EA 2010”). The case reached the Supreme Court and they considered whether a transgender person with a gender recognition certificate that recognises them as female can be regarded as a woman under equality laws. The Supreme Court decision was that for the purposes of the Equality Act 2010, sex equals biological sex and therefore the definitions of ‘woman’, ‘man’ and ‘sex’ are by reference to biological sex and not an acquired gender.

Background

The Gender Representation on Public Boards (Scotland) Act 2018 is an Act of the Scottish Parliament. It sets targets for increasing the proportion of women on public boards. The original definition of a “woman” included people: (i) with the protected characteristic of gender reassignment; (ii) living as a woman; and (iii) proposing to undergo / undergoing / who have undergone a gender reassignment process.

For Women Scotland first challenged the wording in 2022. Following the challenge, a new definition of a “woman” was issued which stated a person with a Gender Recognition Certificate recognising that their gender is female is considered a woman.

The Court Decisions

For Women Scotland challenged the 2022 definition. They argued that sex-based protections should only be available to people who were born female and should not include transgender women. On 13 December 2022 the Court of Session Outer House dismissed the petition. For Women Scotland appealed and on 1 November 2023 the Inner House upheld the decision of the Outer House and dismissed the Appellant’s appeal. For Women Scotland then appealed to the Supreme Court.

The Supreme Court Decision

In March 2025 the Supreme Court ruled that to include persons with a gender recognition certificate in their acquired gender would render certain provisions of the Equality Act unworkable or incoherent, and it is important that the Act be interpreted in a clear and consistent way throughout. The Court took pains to reiterate that transgender people remain protected by the Equality Act from discrimination on the ground of gender reassignment, and can also claim direct and indirect discrimination and harassment on the ground of perception or association with their acquired gender.

The judgment considered the interaction between the Equality Acct 2010 and the Gender Recognition Act 2004. The Supreme Court ruled, unanimously, that the definition of woman and sex in the Equality Act 2010 refer to a biological woman and biological sex rather than what was described as certified gender (as a result of a person changing their gender and gaining a gender recognition certificate reflecting their acquired sex under the 2004 Act).

The ruling means that a person with a Gender Recognition Certificate acknowledging their gender as female should not be regarded as a woman for the purposes of a sex discrimination claim under the Equality Act 2010 and does not fall into that protected characteristic or definition.

The Equality and Human Rights Commission Guidance

Following the Supreme Court’s decision in For Women Scotland v The Scottish Ministers, the Equality and Human Rights Commission issued a short interim update highlighting the main consequences of the judgment. The Code of Practice will be updated to reflect the Supreme Court ruling and, subject to ministerial approval, it will be laid before Parliament before the summer recess.

The short interim update highlights the following:

In workplaces, it is compulsory to provide sufficient single-sex toilets, as well as sufficient single-sex changing and washing facilities where these facilities are needed. Its key message is that trans women (biological men) should not be permitted to use the women’s facilities and trans men (biological women) should not be permitted to use the men’s facilities, as this will mean that they are no longer single-sex facilities.

In services that are open to the public, there is no compulsory requirement to provide single-sex facilities. However, it could be indirect sex discrimination against women if the only provision is mixed-sex.

In workplaces and services that are open to the public:

There are rules about when competitive sports can be single-sex, which the commission intend to address separately in due course.

Schools

Schools must provide separate single-sex toilets for boys and girls over the age of 8. It is also compulsory for them to provide single-sex changing facilities for boys and girls over the age of 11.

Pupils who identify as trans girls (biological boys) should not be permitted to use the girls’ toilet or changing facilities, and pupils who identify as trans boys (biological girls) should not be permitted to use the boys’ toilet or changing facilities. Suitable alternative provisions may be required.

Association Membership

Membership of an association of 25 or more people can be limited to men only or women only and can be limited to people who each have two protected characteristics. It can be, for example, for gay men only or lesbian women only. A woman-only or lesbian-only association should not admit trans women (biological men), and a men-only or gay men-only association should not admit trans men (biological women).

Protection For Transgender Employees

It is important to remember, the Equality Act prohibits discrimination against a person linked to their transgender status, and this includes the fact they are going to transition their gender, are proposing to do so, or have completed that process. That protection applies early, by including an individual who is proposing to undergo a gender reassignment process (as well as those undergoing such a process and those who have changed gender). The Act has specific provisions to ensure that where an individual needs time off or is absent due to the transition process, they are treated consistently with other staff and not denied that time off because of the reason for their absence. Also, there are strict laws which protect an individual who holds a gender recognition certificate giving them privacy rights and restricting the use of any information about their previous gender as special data; this protection applies in the workplace and to those providing services. This decision does not change any of that.

Implications For Employers

The implications will be greatest for businesses providing single-sex services to the public, but all employers should review their provision of single-sex facilities in the workplace. The Supreme Court ruling suggests that the use of single-sex toilet and changing room facilities should be delimited by biological sex but, given the need to ensure dignity, privacy and health and safety of all employees, providing at least some gender-neutral facilities (in separate cubicles, lockable from the inside) is likely now to be a high priority.

Employers may also need to reflect the Supreme Court ruling in any positive action measures or genuine occupational requirements used and in data collection. Staff training should be checked and updated if appropriate and, particularly if the issue has become a hot topic of conversation in a workplace, employers may wish to reiterate the need for mutual respect and tolerance of others’ views – and for care to be taken in how and when views are expressed in a workplace setting.

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