Dr Richard Dune

17-04-2025

Image by JoPanwatD via Envato Elements

The Supreme Court has spoken: Biological sex now defines ‘woman’ in law - what this means for equality, governance, and health and care providers

On 16 April 2025, the UK Supreme Court delivered a landmark ruling that has redefined how sex and gender are interpreted under British law. In the case of For Women Scotland Ltd v The Scottish Ministers, the court ruled unanimously that the legal definition of a “woman” under the Equality Act 2010 refers to biological sex, not gender identity and not even legal gender acquired through a Gender Recognition Certificate (GRC).

In this blog, Dr Richard Dune explores the implications of this ruling across various sectors. Years in the making, this decision now offers long-awaited legal clarity but also carries significant consequences for those working in health and social care, equality policy, inclusion strategies, and organisational governance.

What was this case really about?

At the heart of this high-profile case was a conflict between two major pieces of legislation, outlined below:

• The Gender Recognition Act 2004 allows transgender individuals to change their legal gender by obtaining a Gender Recognition Certificate (GRC), declaring that this change applies “for all purposes.”
• The Equality Act 2010 is the foundational legislation for UK anti-discrimination law. It protects nine characteristics, including sex and gender reassignment, as distinct categories.

The legal question at stake is:

“Does obtaining a GRC change a person’s sex for the purposes of the Equality Act?”

The debate - Two strongly opposed positions

Gender-critical groups and for women Scotland

• Argued that sex-based rights (e.g. access to women-only wards, services, or leadership quotas) must be grounded in biological sex, not gender identity.
• Warned that redefining “woman” to include trans women could erode the integrity of single-sex spaces, impact data collection, and undermine positive action policies.
• Believed the Scottish government had overreached by including trans women in quotas for female representation on public boards.

Trans rights organisations and allies

• Maintained that GRC holders should be legally recognised as women in every context, including under the Equality Act.
• Feared the ruling would strip GRCs of their legal significance.
• Emphasised that trans individuals, especially trans women, deserve recognition, dignity, and safety within public services and society at large.

The court's judgment - What the justices said

In a thorough 88-page ruling, the UK Supreme Court held that:

“The terms ‘woman’ and ‘sex’ in the Equality Act 2010 refer to biological sex, not to gender identity or to the legal effects of a GRC.”

It concluded that interpreting “sex” to include GRC-based identity would create inconsistencies across the legislation, particularly in relation to:

• Pregnancy and maternity protections
• Single-sex exemptions under Schedule 3 of the Equality Act
• Positive action policies and public sector quotas
• Safeguarding in health and care environments.

Key takeaways from the Supreme Court ruling

• The legal definition of sex is binary, male or female, as determined at birth.
• A GRC does not alter a person’s legal sex under the Equality Act.
• Public bodies and regulated services must now base single-sex provisions solely on biological sex.
• The protected characteristic of gender reassignment remains intact, and trans individuals are still protected from discrimination and harassment.
• GRCs retain symbolic and administrative value, but no longer determine eligibility for sex-based legal protections under the Equality Act.

What does this mean for health and social care providers?

The implications for the NHS, local authorities, CQC-regulated providers, and third-sector organisations are wide-ranging and immediate.

Service provision

Providers of single-sex services, such as wards, toilets, changing areas, and women’s refuges, can now lawfully exclude trans women where this is a “proportionate means of achieving a legitimate aim.” This includes safety, privacy, and dignity considerations.

Safeguarding and risk assessment

Safeguarding policies must be updated to clearly distinguish between biological sex and gender identity clearly. In particular, services delivering intimate or personal care must ensure that users are supported by same-sex staff as defined by biological sex.

Recruitment and inclusion

• Positive action programmes targeting women (e.g. in leadership, STEM roles, or board appointments) must apply biological sex definitions.
• Equality monitoring and reporting must also disaggregate data by birth sex, not gender identity.

Equality Impact Assessments (EIAs)

EIAs should be updated to reflect the revised legal definition of sex. While trans individuals’ needs must still be addressed, this now must be done under the gender reassignment characteristic, not sex.

The regulatory response

Equality and Human Rights Commission (EHRC)

• Welcomed the ruling, stating it resolves years of legal ambiguity.
• Announced plans to revise the Code of Practice and single-sex service guidance, with updated guidance expected to be presented to Parliament before summer 2025.
• EHRC Chair, Baroness Kishwer Falkner, noted that this would support duty-bearers to "implement the law with confidence."

NHS England

• Currently reviewing its 2019 same-sex accommodation guidance, which previously based ward placement on gender presentation rather than biological sex.
• A formal update aligned with the Supreme Court ruling is anticipated, potentially impacting bed allocation and care arrangements.

What happens next?

This ruling will not be the final word. Several trans rights organisations, including Stonewall and Scottish Trans, have already voiced strong concerns about the judgment’s broader impact.

There is growing pressure on Parliament to:

• Amend the Equality Act to reflect GRC inclusion, or
• Introduce new legislation specifically safeguarding trans rights in the context of single-sex services.

As the political and legal landscapes evolve, organisations must stay informed, update internal policies, and approach implementation with care and compassion.

Leadership, law and respect - Striking the right balance

This Supreme Court ruling represents a moment of legal clarity, but not social consensus. While the judgment upholds sex-based rights, it also challenges service providers, leaders, and professionals to:

• Apply the law lawfully and proportionately
• Maintain the dignity and safety of all service users
• Engage in respectful communication with stakeholders
• Ensure training and governance frameworks are aligned with the law

This is a pivotal moment to demonstrate leadership rooted in ethics, regulation, and compassion in the health and social care sectors.

Want to move forward confidently after the legal redefinition of ‘woman’?

At The Mandatory Training Group, we’re calling on health and social care providers, governance leads, and equality professionals to share how they’re responding to the Supreme Court’s ruling that defines “woman” as biological sex under the Equality Act.

We want to hear from you:

• How is your organisation applying this legal definition across services and policies?
• What changes are needed in your safeguarding, workforce, and inclusion frameworks?
• What support do you need to ensure lawful, ethical, and respectful implementation?

Click here to discover how ComplyPlus™ can support your organisation through integrated compliance tools, tailored training, and expert consultancy - or explore our full range of online statutory and mandatory training courses to get started today.