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

By Faith Barbara N Ruhinda Updated at 1306 EAT on Tuesday 16 April 2025

This has been a really, really long road, says Susan Smith, the co-founder of For Women Scotland.

She says: “Today the judges have said what we always believed to be the case, that women are protected by their biological sex.

Sex is real and women can now feel safe that services and spaces designated for women are for women and we are enormously grateful to the Supreme Court for this ruling.

The first is that the Equalities Act (EA) provides group-based protections against discrimination on the grounds of sex and gender reassignment.

The second point was that the EA must be implemented in a “clear and consistent” way.

The third point was that interpreting sex as ‘certificated sex’ would create “heterogenous groupings” by cutting across definitions of man and woman in the EA in an “incoherent” way.

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.

The Supreme Court ruling, delivered by Lord Hodge, concluded that the meaning of the terms “sex”, “man” and “woman” in the Equality Act 2010 refer to “biological sex”.

It said that any other interpretation would make the Act “incoherent and impracticable”.

The summary read: “Therefore, a person with a Gender Recognition Certificate in the female gender does not come within the definition of a ‘woman’ under the Equality Act 2010 and the statutory guidance issued by the Scottish ministers is incorrect.”

Campaigners and supporters of For Women Scotland celebrated as they emerged from the supreme court by singing “women’s rights are human rights”.

There was hugging and tears among some of the campaigners.

One woman described those who brought the case all the way to the Supreme Court as “she-roes”.

The campaigners broke into applause as the judges left the courtroom.

All had been warned not to disrupt proceedings while the court was in session, but there was an immediate outpouring of emotion afterwards.

Lord Hodge said the ruling should not be seen as a triumph for one group over another, but the cheering and singing has spilled out onto the street outside the court – this is clearly being celebrated as a win by the group.

There were remarkable scenes inside the Supreme Court after the judges left the bench. Campaigners who had brought this case hugged each other and punched the air. Several of them were in tears.

Susan Smith of For Women Scotland told me: “It’s almost unbelievable after so many years to finally have got a ruling which reflects everything we’ve always said.”

Lord Hodge has now concluded the judgement by saying that they have allowed the appeal by For Women Scotland, having outlined a number of reasons why.

There was an audible intake of breath in the courtroom as Lord Hodge announced that the Equality Act’s definition of a woman is based on biological sex.

There were pats on the back from fellow campaigners for the representatives of For Women Scotland, and the group’s director, Marion Calder, wiped away a tear.

Lord Hodge says the predecessors to the Equality Act used definitions of biological sex, and gender reassignment was added as a separate protected characteristic.

He tells the court that, after “painstaking analysis”, including people with a Gender Recognition Certificate in the sex group would make Equality Act read in an “incoherent way”.

He says that issues relating to pregnancy and maternity can only be interpreted as referring to biological sex, while other parts of the Equality Act refers to “certificated sex” as well.

Judges at the UK Supreme Court have begun delivering a landmark ruling on legal definition of a woman after a challenge brought against the Scottish government.

The appeal at the Supreme Court before Lord Reed, Lord Hodge, Lord Lloyd-Jones, Lady Rose and Lady Simler was heard last November and, after the two-day hearing, the judges said they would “take time to consider very carefully” before issuing their judgement on 16 April.

The UK Supreme Court is about to deliver its landmark verdict on how a woman should be defined in law.

The ruling, which comes after a long-running legal battle between the Scottish government and a women’s group, could have far-reaching implications on how sex-based rights apply across Scotland, England and Wales.

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