UK Supreme Court makes ruling on what defines a woman following Trump executive order in the US

A UK Supreme Court has ruled that the legal definition of a woman is based on biological sex amid Donald Trump's executive order in the US.

On Wednesday (April 16), the Supreme Court ruled transgender women with a gender recognition certificate can be excluded from single-sex spaces if 'proportionate'.

Campaign group For Women Scotland (FWS) brought a series of challenges to the UK's highest court over the definition of 'woman' and whether someone with a gender recognition certificate (GRC) recognising their gender as female should be treated as a woman under anti-discrimination legislation.

The Supreme Court ruled in favour, finding that the terms woman and sex in the Equality Act 'refer to a biological woman and biological sex'.

The UK Supreme Court has delivered its verdict (Dan Kitwood/Getty Images)

Justices Lord Hodge, Lady Rose and Lady Simler said: "If as a matter of law, a service provider is required to provide services previously limited to women also to trans women with a GRC, even if they present as biological men, it is difficult to see how they can then justify refusing to provide those services also to biological men and who also look like biological men.

"Read fairly and in context, the provisions relating to single-sex services can only be interpreted by reference to biological sex."

Delivered by Judge Lord Hodge, the written ruling continued: "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."

Campaign groups celebrate outside court (Dan Kitwood/Getty Images)

Just hours after Trump returned to the White House for a second term as president back in January, he signed an executive order recognizing male and female as the only two sexes.

The order states: " Invalidating the true and biological category of 'woman' improperly transforms laws and policies designed to protect sex-based opportunities into laws and policies that undermine them, replacing longstanding, cherished legal rights and values with an identity-based, inchoate social concept."

As for the UK ruling, some campaigns groups have dubbed today's news as 'wonderful', while trans rights groups have said it's 'not justice, it's erasure'.