The UK Supreme Court has just handed down a significant decision in For Women Scotland Ltd v The Scottish Ministers ([2025] UKSC 16). The judgment settles a long-running legal debate about how the word “woman” is to be understood under the Equality Act 2010 – and whether it includes trans women who have a Gender Recognition Certificate (GRC).

This isn’t just a matter of political or social debate. The decision has very real implications for how businesses apply equality laws, particularly where services, spaces or jobs are gender-specific.

As a solicitor advising small businesses across the UK, here’s what I think you need to know – in plain English.

What was the case about?

The case was brought by For Women Scotland, a feminist organisation, challenging guidance issued by the Scottish Government. That guidance said that a trans woman who has a Gender Recognition Certificate could count towards the target of 50% women on public boards in Scotland.

For Women Scotland argued that this was unlawful. They said that the Equality Act treats “woman” as referring to biological sex, not legal gender – even when someone has gone through the formal legal process of gender recognition.

The Supreme Court agreed.

So what did the Supreme Court actually say?

The Court held that the word “woman” in the Equality Act 2010 means biological woman. The same goes for “man” – it means biological man.

This matters because the Equality Act gives certain legal permissions for sex-based services or roles – such as single-sex toilets, changing rooms, support groups, or hostels. The big legal question was: do trans women with a GRC fall within the term “woman” for those purposes?

The answer now is no, unless Parliament changes the law.

Does this mean trans people aren’t protected by law?

Not at all.

Trans people are still protected under the Equality Act through a separate characteristic: gender reassignment. That protection applies whether or not the person has a Gender Recognition Certificate.

So you cannot, for example, refuse to serve someone or treat them less favourably because they are trans. That would still be unlawful discrimination.

What the Court has said is that when the law refers to sex – male or female – it means biological sex, not legal or acquired gender. That brings important clarity for businesses.

When can businesses provide single-sex services?

The Equality Act does allow businesses to provide single-sex services, as long as doing so is a proportionate means of achieving a legitimate aim.

In plain English, that means:

• There must be a good reason for it

• It must be done carefully and fairly

• It must not go further than necessary

Now that we know “woman” means biological woman, that affects how this exemption works in practice.

Examples where single-sex services might be lawful

Depending on your sector, here are examples where you might lawfully provide sex-specific services:

• Women-only gym classes or changing rooms, particularly where privacy is a factor

• Female-only counselling or support groups, such as for survivors of sexual abuse

• Shared accommodation, such as in hostels or refuges, where privacy and dignity require separation

• Faith-based events or services, where gender separation reflects sincerely held beliefs

• Men-only health initiatives, such as prostate cancer clinics or mental health groups

This ruling makes it easier to justify separating by biological sex in these situations – but that doesn’t give you a free pass. You must still apply your policies lawfully, sensitively and proportionately.

What should business owners do now?

If you run a business where sex-specific services or spaces are provided – or where you’re considering them – this ruling is a good prompt to:

• Review your equality policies, especially where they refer to gender or sex

• Update staff training, particularly for HR, customer-facing staff and managers

• Be clear about your rationale if you are offering a single-sex service

• Keep records to show how decisions were made, in case challenged

• Continue to respect and protect trans individuals, remembering they have separate legal protection

My take

As a solicitor, I welcome the clarity this ruling provides. Legal uncertainty doesn’t help anyone – not women, not trans people, and certainly not small businesses trying to stay compliant.

This judgment draws a clearer line in the sand: when the law talks about sex, it means biological sex. That may not align with everyone’s view of identity, but it’s the current legal position. If Parliament wants to change that, it must do so explicitly (and, I expect it will bow to pressure to do so as well).

For now, it’s about getting your policies right and applying them with sensitivity and fairness.

If you’re unsure where this leaves your business, especially in tricky HR or service provision areas, feel free to get in touch.