The British Supreme Court recently clarified that Women have to be defined by their biological sex in the Equality Act. What could the broader impact of this decision be?
This article has been co-written by Sophie Heine and her daughter Amelie Kelly.

A recent ruling by the UK Supreme Court could have a significant impact on how we talk and perceive sex and gender and their connection. Last April, the court ruled that the definition of women in the Equality Act has to be based on biological sex. We would like to take a brief look at this topic and also at how it could encourage, not only transactivists, but also feminists and anti-feminists to rethink their perception of sex and gender.
The Supreme court Ruling
The UK Supreme Court issued a ruling on 16th April clarifying that the definition of women in the Equality Act (Banning discrimination) had to be understood as based on the biological sex. For the Equality Act 2010, a man is defined as a “male of any age” and a woman as a “female of any age”. The court said that those definitions do not say clearly whether “sex” in the act means biological sex .
The group For Women Scotland challenged the decision to put transwomen in the counting of how many women were present in the Boards of company and this is what led to the Courts decision. The judgment is now giving an authoritative interpretation of the law.
Transactivism and extreme constructivism
Over the last few years, voices have started to rise about the potential dangers of totally separating sex and gender.
The transgender movement had indeed pushed the constructivist argument very far – namely, the argument according to which gender is a pure social construction: the detachment between biological sex and gender becomes extreme in this approach.
The idea is here that, if an individual with a certain biological sex feels that they belong to a different gender from the one normally associated with their biological sex, they should be able to change their identity. For instance, a woman born biologically female who would not feel like a ‘woman’ but would prefer to be considered a ‘man’.
In this perspective, it is not necessarily indispensable for the trans person to actually physically change their sex. Transgender activism has indeed led to the possibility of changing your gender purely based on self-perception (in the UK this is called the gender recognition certificate)
If it is important that the transgender minority be respected and not discriminated against, this approach has led to some problems. For instance, in Scotland, where the law was particularly flexible, a transwoman (individual who was still biological male but was recognised as a woman) was arrested for raping another woman and initially put in a female prison. This is obviously very dangerous and created a lot of reactions from civil society (JK Rowling has become an activist on that matter, ‘For Women Scotland’ was a group against that).
Similarly, transwomen (born men and still physically male but recognised as women) were allowed to compete in female teams in certain sports. This is very problematic since a biological man has on average 20 percent more muscle mass than a woman, which gives an advantage in strength, speed and resistance.
These excesses and aberrations have generated reactions from intellectuals of different obedience in civil society. The group “For Women Scotland”, as mentioned earlier contested the Gender Representation on Public Boards (Scotland) Act which stated that transgender women with a Gender Recognition Certificate (GRC) or those living as women would count towards gender balance on public boards. The anti-trans group 2022 took the Scottish Government to court. They initially lost a judicial review, but were then successful on appeal. In the end, the case then went to the Supreme Court. And the latter ruled in April that women were defined by biological sex under the Equality Act.
This ruling has triggered very negative reactions from the trans community and from transactivists who argue that it will now allows people to discriminate against trans, exclude them from single-sex spaces and force them to reveal their identity. They are also worried that this ruling will lead to the media to convey simplistic and discriminatory messages against trans-people and that this will encourage more hatred and discrimination.
The Court discarded these concerns by saying that a biological sex interpretation will not have the effect of disadvantaging trans people because they enjoy other protections.
We think that some of the concerns felt by transactivists could be valid and that it is absolutely crucial that more laws be passed to protect the transgender minority.
But this ruling could make other parts of the population reflect. More specifically, it could have broader symbolic impacts on feminist and anti-feminist debates around sex and gender. Certainly, this ruling concerns the interpretation of the Equality Act but, symbolically, it could lead to other consequences on how sex and gender are perceived in general. This could affect not only how we perceive discrimination but also other areas of life.
The conservative approach: sex before gender
For a long time, the conservative approach justified inequalities between women and men by invoking religion; the argument then switched to natural and biological arguments (from the 19th century onwards). Initially the arguments were very basic (for ex: women were said to be less intelligent because their brain was smaller); Over the course of the 20th century and in the 21st century, those arguments relied on empirical studies. In this view, biological differences between the sexes (regarding hormones, genes and the brain) translate into social and behavioural differences.
A lot of critical responses highlighted that those studies were very limited in scope and that the current state of science could not actually show clearly how existing biological differences between women and men could explain social and behavioural differences. They also often point at the historical and cultural variations of what is expected from women and men.
For instance, for long, women were deemed unfit to politics because they were considered not able to understand matters outside the home. This is a view that seems totally strange today because society has evolved. This is the same about women taking on traditionally male studies and careers, something that would have seemed impossible decades ago… This evolution is a strong argument to show that a lot of the beliefs on what women are or are supposed to be evolve with the historical and cultural context.
In socio-political spheres, however, there is a strong return of this “differentialist” approach. This is the view held by many conservative and extreme right movements. In some circles, even religion is used again as a justification of inequalities between women and men, but, most of the time, the main argument is naturalist or biological.
The recent court ruling defining women though biological sex could embolden this conservative approach. It is therefore essential that feminists tackle this issue of biology as well rather than rejecting it altogether and leaving it to conservatives.
The feminist approach: gender before sex
One of the main feminist arguments is to distinguish sex and gender: the idea is that, while sex is biological, gender is a social construction. This is a very important distinction as many injustices and inequalities affecting women have been justified by so-called “natural” tendencies.
Thus, feminists have contended that, as Simone de Beauvoir put it in her masterpiece “Le deuxieme sexe”: “On ne nait pas femme, on le devient” (“One is not born a woman, one becomes a woman”). By that, the famous French feminist from the 1960’s meant that our biological sex is not what defines us as women but that society does. In other words, being born with a female sex is not what makes us act, think, behave as “women”. It is society that makes us do so.
Most feminists have adopted this “social constructivist” approach.; What is expected from women in society is called “gender stereotypes”. Those vary according to the historical and cultural context.
Broadly speaking, gender stereotypes on womanhood include the following: women are naturally more empathic, they sacrifice more for their family and children when they become mothers, they are more cooperative than competitive, they are less aggressive, they pay more attention to their appearance, they have a more passive approach to desire and seduction.
Those stereotypes exist for men too (men are perceived as more naturally selfish, more competitive less sacrificial in their parenthood, more aggressive, less focused on their appearance and are more active in expressing their desire).
For feminists, these stereotypes are a problem as such, as they prevent individuals from defining their identity freely but also because they are used to justify huge inequalities. For example stereotypes about empathy and sacrificial motherhood are used to justify why women are supposed to sacrifice much more (their time, energy, career, own family) to raise their children. Most feminists therefore propose to abolish those stereotypes through training and education, in order to create a society beyond gender stereotypes, where everyone can express their own identity freely.
But what if biology does matter from a feminist point of view?
But what about biology? Feminists have been reluctant to talk about that dimension, for fear of the essentialist arguments imprisoning women in their so-called “nature”. However, could it be that this ruling encourages feminists to reflect on biology in a pro-women way?
Feminists, even if they are traditionally reluctant to talk about biology, should start thinking more about the importance of biology, at least in some respects. For instance, they can look at the physical differences that matter in sport. The fact that men have twenty percent more muscle mass on average gives them an advantage in strength, height, weight and speed.
These differences can also have an impact at how we tackle the question of violence between men and women: if men are overall stronger, then it should be clear that in instances of alleged domestic violence between them, the suspicion is more directly against the men. This could even impact on the way police and courts deal with emotional abuse as it is often connected to physical violence or the threat thereof. Even if there are instances of women exerting domestic abuse against men, the fact that the latter are on average stronger makes them more likely to have the upper hand (even , again, when the abuse is mainly emotional as it is often connected with threats of physical abuse).
Other biological differences between the sexes are clear and not contentious such as the ones related to reproduction. How can feminists directly tackle the vulnerabilities arising from female characteristics regarding reproduction? The fact that women can get pregnant, give birth and then tend to breastfeed and nurture a new-born for months or even years creates numerous vulnerabilities from a physical and social point of view. Those vulnerabilities should eb compensated for by society. This is currently the case only to a certain extent (for example, maternity pay is very often linked to a certain length of employment, while it should be derived simply from having had a child).
In other words: even if the argument on gender stereotypes is still very useful, women really need to think about biology in a feminist and emancipatory way rather than leave this topic to conservatives.
References
- Genre ou liberté: Vers une féminité repensée : Heine, Sophie: Amazon.fr: Books, Sophie Heine, Genre ou liberté: Vers une féminité repensée, Academia, 201
- Différentes, libres et égales : Quelques pistes pour parler aux femmes aujourd’hui : Heine, Sophie: Amazon.fr: Books, Sophie Heine. Différentes, libres et égales : Quelques pistes pour parler aux femmes aujourd’hui, Couleur Livres, 2022
- Sophie-Heine_Paper_129.pdf: Sophie Heine, The EU Campaign against Gender Stereotypes: Ideas, Interests and Individual Freedom, Egmont Paper 129, january 2025
- https://uk.news.yahoo.com/scottish-government-changes-guidance-sparked-115702799.html?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cuYmluZy5jb20v&guce_referrer_sig=AQAAAMiQT7gAYZRQBL8_fXog3N3rcJtfh5lmtu-cGymZIsrJmip4QHDu_LtU0ESEPqAnRBWPOJDxlcrLgXwnLrYf4rZbNPVNzVLMoBlL0xoJaCmf8V1vZwEAHPhgXpew4503qhIxjXl0efWweAQ9oRQGk6zj2UQt6peQyLdnnbhyBcbU
- Boy George calls JK Rowling ‘bored rich bully’ as social media feud erupts over trans rights
- The Second Sex Summary | GradeSaver (summary of the famous book nby Simone de Beauvoir)
- The Essential Difference | Simon Baron-Cohen | 9780141011011 | Awesome Books (a differentialist approach)
- Transgender rights movement – Wikipedia
- Supreme Court judgment on the meaning of “sex” in the Equality Act 2010: For Women Scotland – House of Commons Library
- ‘Erosion of our rights’: Trans community reacts to Supreme Court ruling | STV News
- Campaigners warn of Supreme Court ruling impact on trans people – BBC News
Definitions
- The Gender Recognition Act : The GRA allows people whose gender identity does not correspond with the sex originally registered on their birth certificate (trans people) to get a gender recognition certificate (GRC); this gives them legal recognition in their new gender.
- The Equality Act: The EA 2010 bans direct and indirect discrimination, harassment and victimisation on the basis of ‘protected characteristics’ in various circumstances. There are nine protected characteristics, including gender reassignment and sex. The act protects men and women from discrimination in various circumstances on the basis of the protected characteristic of sex.There are some exceptions to the prohibition on discrimination. For example, provisions on pregnancy and maternity discrimination allow differential treatment on the basis of sex.