Trans Rights Upended! UK Supreme Court Rules Legal Definition of “Woman” Based on Biological Sex
In a landmark and highly controversial decision, the UK Supreme Court ruled on Wednesday that the legal definition of the word “woman” is based on biological sex, not gender identity.
This unanimous ruling concludes a legal battle that began several years ago in Scotland and could have far-reaching consequences for transgender rights across the United Kingdom.
What is a “woman”? The legal battle over a word
The case, ongoing since 2018, pitted the Scottish Government—supportive of broader transgender rights—against the advocacy group For Women Scotland, which argued for a strict interpretation of the law based on biological sex. At the heart of the dispute was the interpretation of the 2010 Equality Act, a cornerstone of the UK’s anti-discrimination legislation.
While the Scottish Government argued that trans women with a Gender Recognition Certificate (GRC) should receive the same protections as cisgender women, For Women Scotland contested this, claiming only a birth-sex-based definition aligns with the law.
“Interpreting ‘sex’ as certificated sex would cut across the definitions of ‘man’ and ‘woman’ and thus the protected characteristic of sex in an incoherent way,” a summary of the ruling said, which added that transgender women could be excluded from same-sex facilities such as changing rooms if “proportionate.”
After an initial victory in a Scottish court, the group suffered two legal defeats in 2023. The Supreme Court’s decision now settles the matter in favor of a biological reading of the term “woman.”
Immediate consequences for transgender individuals
The ruling could have concrete impacts, particularly concerning access to single-sex spaces such as women’s shelters, restrooms, hospital wards, or prisons.
LGBT+ organizations fear increased exclusion of trans women from spaces they previously accessed, and view the decision as a troubling political signal amid growing tension around trans rights in the UK.
After the ruling, Ella Morgan, a British trans advocate, told CNN she was deeply fearful over how the outcome would impact “mine and other transgender women’s futures.”
An international ripple effect
The debate over how to define gender is sparking controversy in many Western countries. In the United States, since returning to the White House in January, Donald Trump has introduced several policies targeting transgender people, including their exclusion from the military and new restrictions on gender transition for minors.
This UK ruling may resonate globally, potentially reinforcing conservative stances in other countries.
A divided nation
For years, the UK has been deeply divided over this issue—between radical feminist activists and high-profile figures like J.K. Rowling, who support For Women Scotland, and organizations defending trans rights. Toxic exchanges on social media, accusations of transphobia, and threats on both sides have fueled an ongoing and damaging culture war.
In 2022, the Scottish Government attempted to pass a law that would allow people to change their legal gender without a medical diagnosis, starting at age 16. That law was blocked by the Conservative government in London. Then, in 2023, a scandal erupted over two trans prisoners with histories of violence against women being housed in female prisons—rekindling the debate over access to gendered spaces.