Trans women are not legally women: Supreme Court defines women by 'biological sex' in landmark ruling

16 April 2025, 10:14 | Updated: 16 April 2025, 12:13

The Supreme Court has ruled that 'woman' refers to biological sex under equality laws.

"Woman" and "sex" refer to a biological woman and biological sex in the Equality Act 2010, Lord Hodge has said.

The Supreme Court ruling follows a series of challenges brought by For Women Scotland (FWS), a women's rights campaign group, over the definition of "woman" in Scottish legislation mandating 50% female representation on public boards.

The dispute centres on whether or not somebody with a gender recognition certificate recognising their gender as female should be treated as a woman under the 2010 Equality Act.

Read more: Police should record biological sex after arrests, minister says, after report claims criminals can pick their own gender

Read more: Fencing row erupts as US athlete takes knee instead of competing against transgender athlete

Opening the Supreme Court judgement, Lord Reed called on all parties to respect the "dignity" of the court.

He said: "Some people will be pleased and others will be disappointed.

"Whatever your feeling may be, please respect the dignity of these courts and remain silent until the court is adjourned."

He said the "central question" is how the words "woman" and "sex" are defined in the 2010 Equality Act.

He said: "Do these terms refer to biological woman or biological sex, or is a woman to be interpreted as extending to a trans woman with a Gender Recognition Certificate?

"The unanimous decision of this court is that the terms woman and sex in the Equality Act 2010 refer to a biological woman and biological sex."

He went on to say: "The Equality Act 2010 gives transgender people protection not only against discrimination through the protected characteristic of gender reassignment, but also against direct discrimination, indirect discrimination and harassment in substance in their acquired gender.

"This is the application of the principle of discrimination by association.

"Those statutory protections are available to transgender people, whether or not they possess a gender recognition certificate."

In an 88-page ruling, Lord Hodge, Lady Rose and Lady Simler said: "The definition of sex in the Equality Act 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."

They continued in their written ruling: "A certificated sex interpretation would cut across the definition of the protected characteristic of sex in an incoherent way.

"References to a 'woman' and 'women' as a group sharing the protected characteristic of sex would include all females of any age, irrespective of any other protected characteristic, and those trans women, biological men, who have the protected characteristic of gender reassignment and a GRC, and who are therefore female as a matter of law.

"The same references would necessarily exclude men of any age, but they would also exclude some, biological, women living in the male gender with a GRC, trans men who are legally male.

"The converse position would apply to references to 'man' and 'men' as a group sharing the same protected characteristic.

Activists react after Supreme Court makes ruling on legal definition of a woman

"We can identify no good reason why the legislature should have intended that sex-based rights and protections under the EA 2010 should apply to these complex, heterogenous groupings, rather than to the distinct group of, biological, women and girls, or men and boys, with their shared biology leading to shared disadvantage and discrimination faced by them as a distinct group."

Campaign group Sex Matters, which had made arguments in the case, said the court had given "the right answer".

Maya Forstater, the group's chief executive, said: "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."

Tory leader Kemi Badenoch said: "Saying 'trans women are women' was never true in fact and now isn’t true in law, either.

"A victory for all of the women who faced personal abuse or lost their jobs for stating the obvious.

"Women are women and men are men: you cannot change your biological sex. The era of Keir Starmer telling us that some women have penises has come to an end. Hallelujah!"

First Minister of Scotland John Swinney said: "The Scottish Government accepts today’s Supreme Court judgement. The ruling gives clarity between two relevant pieces of legislation passed at Westminster.

"We will now engage on the implications of the ruling. Protecting the rights of all will underpin our actions."