A lawyer acting for the Scottish Government has told the Supreme Court that a person with a gender recognition certificate (GRC) is “recognised in law” as having changed sex.

Ruth Crawford KC was responding to a legal challenge by For Women Scotland (FWS) over whether trans women can be regarded as female for the purposes of the 2010 Equality Act.

She told the court a person with a GRC, which she said is a document legally recognising a change of sex and gender, is entitled to the “protection” afforded to their acquired gender as set out in the 2010 Equality Act.

“We submit there are only two sexes or genders, and a person whose sex becomes that of a man or woman in consequence of a GRC belongs to that sex, and will have the protection afforded under the Equality Act”, she said.

A change of legal status has been effected, so that person becomes recognised in law as belonging to, or becoming, the sex of their acquired gender

She said a person who becomes a woman “in consequence of a GRC” is entitled to those protections “just as much as others enjoy those protections who are recorded as a woman at birth”.

Ms Crawford told the court by effecting a change in legal status, a GRC has “far-reaching consequences” and is more than “just some legal fiction” or of “symbolic value”.

She said: “A change of legal status has been effected, so that person becomes recognised in law as belonging to, or becoming, the sex of their acquired gender.”

She added a GRC is “no more a legal fiction than adoption”, saying an adopted person is treated in law as the child of their adopter “and no-one else”.

She also said the “inevitable conclusion” of the FWS challenge, if successful, is that trans women with GRCs would “remain men until death for the purposes of the Equality Act”.

Ms Crawford told the court since the Gender Recognition Act was passed in 2004, 8,464 people in the UK had obtained a GRC – which she said was an average of 420 people each year.

She said this “very small number” should “allay” concerns about any impact on “public sector equalities duty obligations”.

Ms Crawford was pressed by the judges on how she squared her position with issues affecting the bodies of people born women, such as pregnancy – the so-called “pregnant man” issue – or cervical screenings.

She responded that the “pregnant man” issue was “very clearly a matter of deep political water” that should either be left for Parliament to resolve, or treated, along with things such as cervical screenings, as a “matter of fact” regardless of a GRC.

The case is the latest in a series of legal challenges brought by FWS over the definition of “woman” in the Gender Representation on Public Boards (Scotland) Act 2018, which mandates 50% female representation on public boards.

The case centres on whether somebody with a GRC recognising their gender as female should be treated as a woman under the 2010 Equality Act.

FWS is seeking to overturn a 2023 ruling by the Scottish courts that treating someone with a GRC as a woman under the Equality Act is lawful.

The group successfully challenged the original Act in 2022 over its inclusion of trans women in its definition of women, with the Court of Session in Edinburgh finding changing the definition of a woman in the Act was unlawful as it dealt with matters falling outside the Scottish Parliament’s legal competence.

Following the challenge, the Scottish Government dropped the definition from the Act and issued revised statutory guidance – essentially, advice on how to comply with the law.

Women are entitled to respect for their identity, privacy and security from male violence and the unwanted and intrusive male gaze

This guidance stated that under the 2018 Act, the definition of a woman was the same as that set out in the Equality Act 2010, and also that a person with a GRC recognising their gender as female had the sex of a woman.

FWS challenged this revised guidance on the grounds sex under the Equality Act referred to its biological meaning, and said the Government was overstepping its powers by effectively redefining the meaning of “woman”.

However, its challenge was twice rejected by the Court of Session, which granted FWS permission to appeal to the Supreme Court in London.

Responding, Aidan O’Neill KC reiterated his call for the court to uphold the appeal, saying it came down to a question of women’s rights, which he said were “human rights”.

He rejected Ms Crawford’s characterisation of gender identities as “fundamental rights”, saying they were not a “trump card” over the rights of women who, he reminded the court, “form the majority of the population”.

He added: “Women are entitled to respect for their identity, privacy and security from male violence and the unwanted and intrusive male gaze.”

He also reiterated arguments made on Tuesday that “sex” in the Equality Act referred to biological sex, and took issue with a number of Ms Crawford’s arguments.

He said adoption was not comparable to a GRC as it only affected the “particular family relationship” of the people involved.

He also pointed to differences in access to abortion between women and trans women, which he said was an “absurd consequence” of the Scottish government’s position.

The judges said they would “take time to consider very carefully” the submissions made, and said they would issue their judgment “as soon as we can”.