In a landmark ruling, the Supreme Court clarified the legal interpretation of the words ‘sex’, ‘woman’ and ‘man’ in Sections 11 and 212(1) of the Equality Act (EA) 2010 with respect to gender reassignment and sexual discrimination following a challenge by For Women Scotland (FWS), a leading feminist organisation. FWS had challenged the statutory guidance issued by the Scottish Ministers under the Gender Representation on Public Boards (Scotland) Act 2018 which stipulated that a trans woman with a full Gender Recognition Certificate (GRC) should be treated as a woman for the purposes of achieving the gender representation objective of 50% women on public boards. FWS argued that this interpretation was unlawful and outside the legislative competence of the Scottish Parliament. FWS contended that the definition of a ‘woman’ under the EA 2010 refers to biological sex, and a trans woman with a GRC is not a woman under this Act, while the Scottish Ministers argued that woman refers to ‘certificated sex’.

The Supreme Court unanimously allows the appeal and ruled that the terms “man”, “woman” and “sex” in the EA 2010 refer to biological sex citing the centrality of a woman’s capacity for pregnancy and giving birth, declaring that such provisions are “unworkable unless 'man' and 'woman' have a biological meaning”. Crucially, they further noted that the Sex Discrimination Act 1975 defines a ‘man’ and ‘woman’ in relation to biological sex and that “interpreting 'sex' as certificated sex would cut across the definitions of “man” and “woman” and thus the protected characteristic of sex in an incoherent way [thus] creating heterogeneous groupings.”

This decision has significant implications for the interpretation of anti-discrimination law, ensuring that the protections afforded by the EA 2010 are applied consistently and coherently. Although this case is not an employment case, prima facie, the ruling will impact separate-sex and single-sex services and will have important implications for gender pay gap reporting. However, this judgement should not be regarded as diminishing the protections afforded to trans employees in relation to discrimination, harassment, and victimisation on the grounds of gender reassignment. Employers must continue to create a workplace that is inclusive and respectful of trans employees. However, for the purposes of the Equality Act 2010, they will not be recognised on the basis of their certified sex.