Equality Act Update: Supreme Court Clarifies Definition of Sex

In April 2025, the UK Supreme Court made an important decision clarifying the definition of ‘sex’ in the Equality Act 2010. The Court ruled that ‘sex’ refers to a person’s biological sex, rather than their gender identity.

This ruling has significant implications for employers and service providers across the UK.

What Was Decided?

In the case of For Women Scotland Ltd v The Scottish Ministers, the Supreme Court confirmed that:

• The Definition of Sex under the Equality Act means biological male or biological female.
• A transgender person, even if they hold a Gender Recognition Certificate (GRC), is not treated as their acquired gender for the purposes of ‘sex’ protections.
• Single-sex services and spaces can lawfully be provided based on biological sex, where justified.

You can read more about the ruling in this BBC News article.

The Equality and Human Rights Commission (EHRC) has also issued interim guidance to support employers and service providers.

Why This Ruling Matters

The Equality Act 2010 is the key piece of legislation protecting people from discrimination in the workplace and in the provision of goods and services. Until now, the lack of clarity over the definition of sex has caused uncertainty for employers when designing policies or managing sensitive situations.

This ruling provides legal certainty but also creates new areas of risk:

• Employers offering single-sex spaces (such as toilets, changing rooms or sleeping accommodation) must now apply biological sex, not gender identity.
• There is greater potential for discrimination claims if organisations fail to carefully balance rights relating to both sex and gender reassignment.
• Organisations need to ensure that policy decisions can be objectively justified, particularly where they involve any form of exclusion.

It’s vital for businesses to review their approach to equality, diversity, and inclusion in light of this ruling.

What Employers Should Do Now

1. Review Your Policies and Documentation

• Check all HR policies, staff handbooks, diversity statements, and risk assessments.
• Update any wording around ‘sex’ to reflect biological sex where necessary.
• Pay special attention to policies covering toilets, changing rooms, uniforms, and recruitment.

2. Assess Facilities and Services

• If you operate any single-sex services or facilities, review whether access is organised based on biological sex.
• Be prepared to objectively justify any policies that might restrict access based on sex, balancing legal compliance and employee dignity.

3. Update Equality and Diversity Training

• Train HR teams, line managers, and employees on the new interpretation of ‘sex’ under the Equality Act.
• Include guidance on managing situations involving transgender employees respectfully and lawfully.

4. Communicate Changes Clearly

• If policies change, communicate openly with your teams.
• Explain the reasons behind any updates and reaffirm your organisation’s commitment to inclusion and respect for everyone.

5. Seek Professional HR Advice

• Managing these changes can be complex and sensitive.
• Working with an HR partner like Kingswood Group will ensure your approach is legally compliant and carefully balanced.

Important: Balancing Rights

While the Supreme Court ruling clarifies the definition of ‘sex’, it does not remove protections for transgender individuals under the Equality Act’s separate protected characteristic of gender reassignment.

Employers must continue to:

• Protect individuals from harassment, victimisation, and discrimination on the basis of gender reassignment.
• Take a case-by-case approach when sensitive issues arise, considering reasonable adjustments where appropriate.
• Maintain a respectful, inclusive environment where everyone feels safe and valued.