UK Supreme Court rules legal definition of man and woman is based on biological sex

The U.K. Supreme Court ruled that the legal definitions of “man” and “woman” are based on a person’s “biological sex” as assigned at birth. The Court issued its ruling with a unanimous 5-0 decision, and the anti-transgender activists hailed the decision.

For Women Scotland (FWS), an anti-trans advocacy group, challenged changes to Scotland’s Gender Recognition Act, arguing to the U.K.’s highest court that Scotland should not be allowed to include trans women who have gender recognition certificates (GRCs) as “women” for the purposes of meeting gender equity quotas on public boards. 

The five justices largely sided with FWS in their decision, writing that including cis and trans women in the same legal sex category “would cut across the definitions of ‘man’ and ‘woman’ and thus the protected characteristic of sex in an incoherent way.”

“The meaning of the terms 'sex', 'man', and 'woman' — as used in the U.K.’s Equality Act 2010, which bars discrimination based on sex, sexual orientation, and gender reassignment — refer to biological sex, as any other interpretation would render the Equality Act 2010 incoherent and impracticable to operate,” the Court ruled.

The Court’s decision undercuts the central purpose of the Gender Recognition Act and goes against 20 years of equality law in the U.K.