Supreme Court: Ruling on the definition of a woman in the Equality Act 2010

Background

This dispute began in 2018 following the Scottish Parliament’s introduction of the Gender Representation on Public Boards (Scotland) Act 2018 (the Act), which aimed to increase the representation of women on public boards. In 2022, For Women Scotland (a Scottish campaign group) challenged this Act because the definition of a woman provided for in the Act included any person ‘who has the protected characteristic of gender reassignment if that person was living as a woman and was proposing to undergo or had undergone a process for the purpose of becoming female’.

The Court of Session found that the definition was unlawful as it involved an area of law reserved to the UK Parliament. The Scottish Government issued new statutory guidance stating that under the Act, a woman was the same as under the Equality Act 2010. It also stated that a person with a Gender Recognition Certificate recognising their gender as female was considered a woman for the purposes of the Act.

For Women Scotland challenged this revised guidance on the grounds that under the Equality Act 2010, sex meant “biological sex” and that the Government was attempting to redefine the meaning of ‘woman’. This challenge was rejected by the Outer House of the Court of Session in 2022 and the Inner House in 2023. This decision was then appealed to the Supreme Court and finally decided on 16 April 2025.

Supreme Court decision

The Supreme Court held that ‘sex’ in the Equality Act 2010 means biological sex. A ‘woman’ does not include a transgender woman with or without a gender recognition certificate.

The Court held:

• The terms ‘man’, ‘woman’ and ‘sex’ in the Equality Act 2010 refer to biological sex. If sex through a gender recognition certificate counted as ‘sex’ under the Equality Act 2010, that would make the legislation less coherent.
• Differentiating rights based on possession of a gender recognition certificate would unfairly divide the trans community and it would create issues for service providers who cannot lawfully ask if someone holds a gender recognition certificate.
• Protections for others such as lesbian only spaces and associations would be eroded.
• Legal provisions rely on a consistent biological definition of sex. For example, those concerning single-sex services, communal accommodation and medical care.

The Court emphasised that transgender individuals remain protected as the characteristic of gender reassignment is protected under the Equality Act 2010.

Implications for employers

Whilst the focus was on the question of whether a trans woman with a gender recognition certificate is a ‘woman’ under the Equality Act 2010, there are wider implications arising from the decision. It’s worth noting that protections from discrimination and the exceptions remain as they always have been under the Equality Act 2010, however how we interpret these is now different.

Employers should take note of these as the Supreme Court ruling applies to Scotland, England and Wales.

1. Access to women only roles and services

• The Equality Act 2010 currently provides that employers can take lawful and proportionate ‘positive action’ in certain circumstances where persons who share a protected characteristic suffer a disadvantage, have particular needs or are disproportionately under-represented. Where an employer takes positive action measures aimed at supporting those of a particular sex, this is limited to those with the particular biological sex only.
• The Equality Act 2010 also currently provides for an exception where, having regard to the nature or context of the work, being of a particular protected characteristic is an occupational requirement. Again, the requirement must be a proportionate means of achieving a legitimate aim. This is key.

Therefore, in cases where an employer wishes to be able to rely upon the exception that there is a general occupational requirement for a person holding a role to be a particular sex, the role must only be available to those of a particular biological sex.

• The Equality Act 2010, under conditions, allows service providers and providers of facilities to restrict access to services or facilities to those who share a protected characteristic; alternatively, the provider can provide separate services for people who share a protected characteristic. Generally speaking, restricting access in this way must be a proportionate means of achieving the organisation’s legitimate aims, but there are circumstances where a failure to provide single sex facilities might be considered unlawful.

With clarity on the definition of ‘sex’, this means that services that are restricted based upon sex, must be restricted based upon biological sex only.

2. Need for policy reviews

It’s important that employers and service providers review and update their policies to ensure they align with the ruling.  This is particularly the case for those who have (or are obliged to have) single-sex policies relating to, for example, changing rooms and toilet facilities.

The Equality and Human Rights Commission (EHRC) has issued interim guidance.

Under that guidance, in workplaces and services that are open to the public:

• Trans women should not be allowed to use the women’s facilities
• Trans men should not be allowed to use the men’s facilities
• The law allows, in some circumstances, for trans women to not be allowed to use the men’s facilities and trans men not to be allowed to use the women’s facilities.

However, trans people should not be put in a position that there are no facilities for them to use. Where possible, there should be mixed-sex toilet, washing or changing facilities in addition to single-sex facilities. Where facilities are in lockable rooms (not cubicles) which are intended for single use, they can be used by all.

Schools in England and Wales must provide separate single-sex toilets for girls and boys over the age of eight and single sex changing facilities for girls and boys over the age of eleven.  In Scotland, schools must provide separate single-sex toilets regardless of age.  Pupils who identify as trans girls are not allowed to use the girls’ toilet or changing facilities; equally, those who identify as trans boys must not use the boys’ facilities. There is a variety of other rules relating specifically to schools, including single-sex schools.

Rules about when competitive sports can be single-sex will be addressed in separate guidance from the EHRC to follow.

Continued protection for trans people

Although this case provides clarity in terms of the statutory definition of a ‘woman’ in the Equality Act 2010, organisations must continue to ensure that all staff and service providers, including from the trans community, are treated with dignity and fairness and are protected from discrimination and harassment.

Under the Equality Act, there is protection from discrimination on the basis of “gender reassignment” (the term used in the Equality Act). This includes protection from less favourable treatment because of their trans status; protection extends to someone who is discriminated against because of their biological sex or because they are perceived to be a particular biological sex.

How we can help

Overall, the way the Equality Act will now be interpreted has changed considerably. Employers need to take note and adjust their practices accordingly.

The decision and the EHRC interim guidance remain controversial and we expect to see legal challenge to the decision in the European Court of Human Rights.

If you require specific advice on this topic please contact, Jemma Forrest or send us an enquiry here.