The definition of ‘sex’ under the Equality Act 2010: the Supreme Court’s guidance

A trans person who is at least 18 years old can apply for a ‘gender recognition certificate’ (GRC), which legally recognises their ‘acquired gender’. Under Section 9(1) of the Gender Recognition Act 2004 (the ‘GRA 2004’), once the GRC is issued, a person’s gender becomes ‘for all purposes’, their acquired gender. However, Section 9(3) states that Section 9(1) GRA 2004 does not apply if any other provision of the GRA or any other law or regulation says something different.

Under the Equality Act 2010, there are nine protected characteristics, two of which are ‘gender reassignment’ (Section 9 EA 2010) and ‘sex’ (Section 11 EA 2010). The protected characteristic of sex under the EA 2010 is binary and refers only to ‘man’ and ‘woman’. Section 212(1) of the EA 2010 defines ‘woman’ as ‘a female of any age’. 

Factual background

On 9 March 2018, the Gender Representation on Public Boards (Scotland) Act 2018 (the ‘GRPBSA 2018’) received Royal Assent. Under Section 2 of the GRPBSA 2018, the definition of ‘woman’ included a person who had the protected characteristic of gender reassignment under the EA 2010. 

This legislation required positive action to be taken by businesses to redress gender imbalances on public sector boards in Scotland. And so, one of the objectives was that 50% of the non-executive members should be women.

On 19 April 2022, the Scottish government produced revised statutory guidance stipulating that a ‘woman’, for the purposes of the GRBPSA 2018, included trans women with a GRC.

Following the publication of the revised statutory guidance, For Women Scotland (an advocacy group that campaigns to strengthen the rights of women and children in Scotland) brought judicial review proceedings against Scottish ministers. For Women Scotland (FWS) argued that the definition of ‘woman’ under EA 2010 should be taken only as a reference to a biological woman.

Both the Outer House and the Inner House of the Court of Session ruled that the revised statutory guidance was not unlawful. This was on the basis of Section 9(1) of the GRA 2004 stating that upon a full GRC being issued, the person’s gender becomes their acquired gender ‘for all purposes’. It was, therefore, wrong to state that the definition of woman under Sections 11 and 212(1) of the EA 2010 only referred to biological sex.

FWS appealed to the Supreme Court.

The Supreme Court’s decision

The Supreme Court unanimously upheld FWS’s appeal, holding that parliament had intended the EA 2010 to refer to ‘man’, ‘woman’ and ‘sex’ as references to biological sex only. The statutory guidance issued by the Scottish government was therefore incompatible with the EA 2010 and was incorrect. Therefore, trans women holding a GRC could not be included as ‘women’ for the purposes of the GRBPSA 2018.

The Supreme Court held that Section 9(3) of the GRA 2004 allowed Section 9(1) of GRA 2004 to be interpreted in a manner that was coherent and compatible with the EA 2010 (which, the Supreme Court reasoned, could only define ‘sex’ as biological sex and binary in nature under Sections 11(a) EA 2010 and 212(1) EA 2010 as it referred to ‘man’, ‘male’, ‘woman’ and ‘women’).

The Supreme Court argued that a binary interpretation of sex would allow for greater legal certainty, consistency and practicality in the application of the EA 2010. Further, the court held that the definition of sexual orientation under Section 12 of the EA 2010 only made sense if references to sex were references to biological sex.

Lessons from this case

This case has profound implications for (trans) employees, employers and other organisations. 

Most immediately, the Supreme Court’s decision establishes that trans women employees (whether they possess a GRC or not) are not defined as ‘women’ as per the Equality Act 2010. As a result, they are not primarily protected under Section 11 of the EA 2010 (the protected characteristic of ‘sex’), but rather under Section 7 (the protected characteristic of ‘gender reassignment’). 

However, trans people would continue to be protected against discrimination or harassment because they are perceived to possess the protected characteristic of sex.

Employment lawyers advising trans clients should be cognisant of the Supreme Court’s guidance when advising on options available if employees are being treated poorly in the workplace.

The Supreme Court’s decision also has implications for employers, as follows:

• employers should take prompt steps to update their policies and procedures to reflect the Supreme Court’s interpretation of the EA 2010; and
• employers must ensure that all of their staff, including trans employees, are treated fairly and that they are protected from discrimination and harassment.

Service providers, charities and other organisations will be able to lawfully exclude trans people (whether they have a GRC or not) where the EA 2010 allows for the provision of separate or single-sex spaces or activities.

The Equality and Human Rights Commission (EHRC) is expected to produce an updated statutory code of practice on discrimination in goods and services, public functions and associations, taking into account the Supreme Court’s judgment, by summer 2025.

Chris Hadrill is a Partner in the employment team at Redmans.