Posted Date: 8th May 2025
The UK Supreme Court recently clarified the definition of "sex" under the Equality Act 2010.
In a landmark ruling on 16th April 2025, the Court determined that "sex", a protected characteristic under the Act, refers to biological sex, not gender identity or the acquired gender recognised through a Gender Recognition Certificate (GRC).
This means that, under the Act:
A ‘woman’ is a biological woman or girl (a person born female)
A ‘man’ is a biological man or boy (a person born male)
Therefore, if a person identifies as trans, they do not change sex for the purposes of the Act, even if they have a Gender Recognition Certificate (GRC), meaning:
A trans woman is a biological man
A trans man is a biological woman
This decision also emphasises that the Equality Act treats "sex" and "gender reassignment" as distinct and separate protected characteristics.
What does this mean for employers?
Following the Supreme Court’s decision, the Equality and Human Rights Commission have recently issued an interim update to provide guidance, the relevant details of which are set out below.
Employers must provide sufficient single-sex toilets, as well as sufficient single-sex changing and washing facilities if these facilities are needed.
If workplaces and services that are open to the public:
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
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
(Equality and Human Rights Commission, 2025)
A Code of Practice will be put towards the Government by end of June. Check out our blog for any further updates.