Is Sex Just About Biology? Taking A Look At The New Supreme Court Ruling
As you may know, on the 16th of April 2025, The Supreme Court announced a unanimous decision stating that “The terms Woman and sex in the 2010 Equality Act refer to a biological woman and biological sex.”
The ruling sent shockwaves through the trans and intersex community and rattled their allies, who gathered to protest just days later, holding up banners that read Protect Trans Lives and Smash the Cis-tem.
Worryingly, the new ruling seems to backtrack on the definition of sex established in the 2004 Gender Recognition Act that introduced the concept of ‘certificated’ sex. After the ruling, the idea that a gender recognition certificate (GRC) meant a change of sex ‘for all purposes’ seems to have gone out the window.
So the next question is, does the ruling make sense from a biological perspective?
Does the Biology Add Up?
The campaign group For Women Scotland argued that sex-based protection should only apply to people that are female.They announced in court that sex is an ‘immutable biological state’ and that interpreting the words man and woman in a way that made ‘common sense’ was their aim.
But, does this add up with what we know about biological sex?
Biological sex is tricky to pinpoint, but most scientists measure biological sex based on someone’s reproductive organs, physical characteristics, chromosomes, and hormones. It’s generally assumed that a man will have XY chromosomes, be fueled by testosterone, and have a penis and testicles.
On the other hand, women will present with XX chromosomes, have a more complex set of hormones that are governed by a menstrual cycle, and possess a vulva and womb (which is made up of the ovaries, uterine tubes, uterus, cervix, and vagina).
Seems pretty straightforward, right? Well… Not really. The intersex community is a great example of how blurry biology is and how much it can stray from the binary. Intersex people are born with a variety of differences in their sex traits and reproductive anatomy. They can present with both male and female biological traits, making it hard to categorise them as either male or female.
You might be thinking ‘Yes, but I’m sure very few people are actually intersex.’ Well, upper estimates suggest that around 2% of the general population is intersex – that’s more than the entire population of Japan!
To give you some examples of how intersex individuals might present, some can be born with a set of XXY chromosomes, known as Klinefelter syndrome (although I hate the word syndrome), or a set of XYY chromosomes, known as Jacobs syndrome.
I wonder then, how the new biological definition of sex plans to address intersex individuals.
Pidgeon Pagonis is an intersex activist and writer who underwent non-consensual intersex surgery at a very young age. Doctors removed their testes and performed a clitoridectomy and labiaplasty (forms of cosmetic surgery on the clitoris and vulva) to make their genitals look more ‘female’.
There are currently no laws in the UK banning genital normalising surgeries performed on intersex infants. The message of these forms of surgery is clear – society wants people to fit in the binary biological model of sex. It seems ironic too that doctors are allowed to make decisions about a person’s body and biological sex, yet trans individuals making these same decisions autonomously are so heavily stigmatised and marginalised.
When it comes to biological sex, a binary approach is reductive and overly simplistic. The intersex community reminds us that biology is not as simple as black and white, ‘man or woman’; and the trans community reminds us that sometimes our biology doesn’t match our lived experience and identity. Sticking to a binary model of biological sex marginalises entire communities and fails to recognize the array of human bodies and identities.
What Will the Ruling Mean for Trans Rights?
The court said they “counsel against reading this judgment as a triumph of one or more groups in our society at the expense of another – it is not.” They stated that trans people will still be protected under the 2010 Equality Act against discrimination and harassment in their acquired gender.
But, as Dr Nick McKerrell rightly pointed out, this new legislation means that transgender women with a GRC who are excluded from single-sex spaces won’t be able to raise this as an issue of discrimination. So, aren’t we removing transgender people’s abilities to report discrimination when it does occur?
Helen Belcher, Chair of the trans rights group TransActual, responded by saying “Trans communities are devastated by today’s ruling. The Supreme Court chose not to hear from any trans people, preferring instead to listen to exclusionary groups.” It seems that even in the process of making this decision, trans people were excluded and their voices were neglected whilst those of For Women Scotland were amplified in a room where their opinions were not questioned nor contradicted. It got me thinking – isn’t exclusion one of the most aggressive forms of discrimination?
In a more hopeful tone, Helen Belcher added ‘Yet, we have come through worse before and are not going away. Whatever the world throws at us, we will be back, each time, stronger and bolder than before.’
Ultimately, this is what it boils down to. You can oversimplify biology to suit a binary perspective for the sake of law and policy-making – but people’s experiences and identities are not binary. The Supreme Court Ruling can’t erase entire communities. But sadly, it can make their lives harder…
Toilets, Toilets…
The debate around trans identities and biological sex always seems to lead us back to the same question – what about toilets?
Women have argued that cisgender men could pretend to be transwomen to get into women’s bathrooms. There is an underlying fear of putting women at risk of harassment. But when women are being harassed in every public space imaginable, from their workplace to their own homes – why is the focus not on educating young men about consent and pooling our resources into comprehensive RSHE instead of debating who should use what toilets?
The new court ruling will impact a number of public spaces and procedures and has already had some concerning implications. British Transport Police announced that in line with the new court ruling, and whilst everyone got their heads around the full implications, any strip searches performed in custody would be done ‘in accordance with the biological birth sex of the detainee.’
From the 1st of June 2025, trans women will be excluded from playing in female football teams in England by the Football Association. The worry is that this trend could continue, impacting hospital wards, women’s shelters, and an increasing number of public facilities.
Many have pointed out that trans people should advocate for their own kind of public spaces, but since we currently don’t have a set of ‘third sex’ infrastructure in place the Supreme Court ruling puts intersex, non-binary, and trans communities at a clear risk of exclusion. There’s also been no mention of the intersex community in all of this.
As Janey, a 70-year-old transwoman who transitioned in 1979 said, “Rights can be knocked out in a second”. She describes how fears she had when she first began transitioning are resurfacing and she worries that her security could be at risk.
How Can We Protect ALL Women?
Despite the ruling, businesses have been popping up on my Instagram feed with hopeful messages that let trans people know they are welcome and safe in their spaces. Already, a trans former judge, Dr Victoria McCloud, has announced she plans to challenge the new ruling and take the government to the European Court of Human Rights!
Policies will take a while to be ironed out and implemented. My hope is that in the meantime activists, charities, and politicians will speak out against the ruling and find ways to protect anyone who doesn’t identify with the sex they were assigned at birth or who doesn’t neatly fit into either category.
I also believe that sex education has a big part to play, and that’s where Split Banana comes in!
Education and inclusivity will always be at the heart of what we do, and we will continue to provide safe spaces where people can come together to learn how to build relationships based on mutual respect, joy, comfort and safety.
The opportunity to help educate people about the diverse experiences of sexuality and gender identities is one of the things that drew me to Split Banana and motivated me to become a Youth Advisor for their organisation – and I’m so glad I did!
Willow Jackson is a Split Banana Youth Advisor & Teen Sex Educator.
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Split Banana’s Advice to Schools:
Trans children are more likely to face bullying and discrimination than their peers. Have regular check-ins with these students about their experiences at school to ensure that their wellbeing is prioritised.
Don’t be afraid to teach what trans or intersex identities are. Teaching an RSE which challenges gender binaries supports an understanding of gender which is free from dogmatic stereotypes. This benefits everyone!
Ask your Union what steps they are taking to pressure the government to provide clear guidance, made in consultation with the trans community.
Remember that you don’t need to follow the draft guidance on gender questioning children - this was widely criticised by nearly all LGBTQIA+ organisations for not consulting transgender children, families of transgender children or transgender organisations. It is important for guidance which centres the experience of the people it’s affecting the most.
Reinforce anti-discrimination messaging throughout the school especially around gender-based violence and discrimination.
Check out our ‘Identity’ resources for young people, here.
Don’t work in a school but want to support trans children?
Let schools know that you support trans children! Thank them for prioritising their safety and wellbeing. Show them that there is a huge amount of people who want trans children to have a safe and joyful school experience.
Write to your MP to express your concern and to ask them how they are consulting the trans community when providing guidance for schools.
Support trans people! Speak out when you see discrimination and fight for a society free from gender-based violence.
