UK Supreme Court rules 'woman' means biological sex, excludes trans women

The UK Supreme Court on Wednesday (April 16) made a landmark decision making it clear that, under the Equality Act 2010, "woman" is defined only as someone assigned female at birth, thereby excluding trans women from that legal definition, according to a CNN report.

 

The unanimous ruling by the court said that the Equality Act relies on biological sex, rather than gender identity, as the foundation for legal definitions of "man" and "woman." 

The court, in giving its ruling, said: "The Supreme Court unanimously allows the appeal. It holds that the terms 'man,' 'woman,' and 'sex' in the EA 2010 refer to biological sex. Lord Hodge, Lady Rose and Lady Simler give a joint judgment, with which the other Justices agree."

 

 

The ruling went on to add: "The definition of sex in the EA 2010 makes clear that the concept of sex is binary, a person is either a woman or a man. Persons who share that protected characteristic for the purposes of the group-based rights and protections are persons of the same sex and provisions that refer to protection for women necessarily exclude men. Although the word 'biological' does not appear in this definition, the ordinary meaning of those plain and unambiguous words corresponds with the biological characteristics that make an individual a man or a woman. These are assumed to be self-explanatory and to require no further explanation. Men and women are on the face of the definition only differentiated as a grouping by the biology they share with their group."

Court sides with biological definition

It is still the case that transgender individuals are protected under the Equality Act under safeguards against indirect discrimination regardless of whether or not they hold a GRC.

 

"Accordingly, transgender individuals (regardless of whether they possess a GRC) are afforded protection by the indirect discrimination provisions of the EA 2010 without the necessity for a certificated sex reading of the EA 2010, both in respect of any specific disadvantage experienced by them as a group of persons having the characteristic of gender reassignment and, where members of the sex to which they identify are placed at a specific disadvantage, insofar as they are also placed at that disadvantage. Again, this does not involve any practical disadvantage or consist in any incongruity between the claim and the position of the individual in society. Rather, the claim will be based on the facts of a specific shared disadvantage. Transgender individuals are also protected against indirect discrimination where they are placed at a specific disadvantage that they share with members of their biological sex," the court added. 

The organisation 'For Women Scotland', which supports gender-critical perspectives and is funded by author JK Rowling, has insisted that the Equality Act exclusively defines a woman as a person born biologically female. Gender-critical campaigner and co-founder of Sex Matters, the organisation that defended 'For Women Scotland' in the Supreme Court case, Maya Forstater, has hailed the decision.

 

“We are delighted that the supreme court has accepted the arguments of 'For Women Scotland' and rejected the position of the Scottish government. The court has given us the right answer: the protected characteristic of sex – male and female – refers to reality, not to paperwork,” she said.

 

What is the UK Supreme Court case on defining ‘woman’ about?

 

At the heart of the case was a central question: Should sex-based legal protections apply to anyone with a Gender Recognition Certificate (GRC), or only to those born female? The Scottish government says that once someone holds a GRC, they should be recognised as their acquired gender in every legal sense.

 

Government lawyer Ruth Crawford KC told the court: “A person who has become the sex of their acquired gender is entitled to the protections of that sex.”

 

But For Women Scotland strongly disagrees, arguing that the law was designed to protect individuals based on biological sex, not legal status. Their lawyer, Aidan O’Neill KC, argued: “Sex is an immutable biological state,” and urged the court to retain a “common sense” interpretation of the words man and woman.

 

Why the legal definition of ‘woman’ could reshape gender laws

 

This isn’t just a technical legal debate. The ruling could impact everyday life by affecting:

 

- Who can access single-sex spaces like changing rooms, shelters, and hospital wards

 

- Equal pay rules and workplace protections

 

- Maternity rights and participation in women’s sports

 

- The future of gender law reforms in the UK

 

How the legal battle over gender recognition in the UK began

 

The legal dispute began in 2018, when the Scottish Parliament passed legislation to promote gender balance on public boards. For Women Scotland challenged the law, saying transgender women should not count toward the statutory female quota.

 

The case later reached the UK Supreme Court in London, where judges considered whether the 2010 Equality Act defines “sex” by biological characteristics or through legal recognition under the 2004 Gender Recognition Act.

 

How the UK is split over gender identity and transgender rights

 

The verdict comes at a time of heightened public debate over gender identity, women’s rights, and trans protections.

 

Transgender rights groups fear that the ruling could erode existing protections under anti-discrimination laws. Organisations such as Amnesty International warn that the ruling may mark the “thin end of the wedge” — potentially affecting the rights of other marginalised groups as well.

 

Even the Equality and Human Rights Commission has intervened, calling for the law to be updated to remove ambiguity and avoid future litigation.