Explainer on the UK Gender Case

What was and wasn't decided and what (if anything) might it mean for NZ?

Q: Did the UK Supreme Court just make a ruling in relation to trans issues?

A: Yes. The UK Supreme Court ruled that under the Equality Act 2010, the word "woman" refers to biological females. This means that trans women, including those with a Gender Recognition Certificate, are not included in the definition of "woman" for the purposes of that law.

The Court said that sex and gender reassignment are separate protected characteristics under the Act and must not be treated as the same thing.

Q: Does this decision apply across the UK legal system?

A: No. The decision applies only to how the words “woman” and “sex” are interpreted in the Equality Act 2010. It does not change the meaning of those words in other laws or across the legal system more generally.

Q: How can a common word have meaning in one law and a different one in another?

A: In law, words can have different meanings depending on the purpose and context of the statute. Legislators often define words within an Act to show what they mean for that law alone. For example, in New Zealand, the word “child” can mean someone under 16 in one law, under 18 in another, and under 20 in a third. It depends on what the law is trying to do. This is a normal and accepted feature of statutory interpretation in most places.

Q: What are the practical implications of this ruling in the UK?

A: Public authorities and organisations applying the Equality Act 2010 must treat “woman” as meaning biological female. This affects how sex-based rights, services and quotas are applied. For example, policies about women-only spaces, public board appointments or protections related to pregnancy and maternity must be based on biological sex. Trans women are still protected under the separate category of gender reassignment, but they cannot be included in provisions that rely on the protected characteristic of sex.

Q: Who was the defendant and what were they arguing?

A: The defendant [more properly, the respondent] was the Scottish Government. They argued that trans women with a Gender Recognition Certificate should be counted as women for the purposes of public board quotas. A Gender Recognition Certificate is a document issued under the UK’s Gender Recognition Act 2004. It allows a person who has transitioned to be legally recognised as their acquired gender for most legal purposes.

The Scottish Ministers said that having a GRC meant someone should be treated as their acquired sex under the Equality Act 2010. The Supreme Court rejected that argument.

Q: Why did the Court reject this reasoning?

A: It’s a long judgment. However, imo the key legal reasoning is found in paragraphs 167 to 197 of the judgment, which is kind of the “doctrinal engine” of the decision. Here’s how it breaks down:

• Statutory meaning must be consistent
  The Court said that when interpreting a statute, words must be read in context and in a way that gives clarity and coherence. A word like “woman” should mean the same thing throughout the Equality Act unless Parliament clearly said otherwise.

• Sex and gender reassignment are separate
  The Equality Act lists sex and gender reassignment as different protected characteristics. The Court said this shows Parliament meant to keep the two separate. Treating a person with a GRC as having changed sex under the Act would blur that line.

• The Act assumes sex is biological
  The Equality Act defines “woman” as “a female of any age” and “man” as “a male of any age.” The word “biological” is not used, but the Court said this is the ordinary meaning. The law assumes sex is binary and tied to biology.

• A GRC-based definition causes problems
  If a GRC changed a person’s sex under the Act, it would lead to confusion. For example, a trans man (who is biologically female but has a GRC saying male) might lose protections for pregnancy and maternity, even though he can still get pregnant. A trans woman (biologically male but with a GRC saying female) might be included in women-only spaces, even though the law is meant to protect those who face disadvantage due to being biologically female.

• GRC status is private and hard to verify
  GRCs are confidential and not publicly visible. If legal sex under the Equality Act depended on who has a GRC, then public bodies would not know who qualifies for sex-based rights unless people disclosed personal medical or legal documents. This would make the law hard to apply.

• Some protections only make sense for biological females
  Parts of the Equality Act, such as those covering pregnancy and breastfeeding, only apply to people who are biologically female. The Court said the law would stop making sense if the word “woman” included people who cannot become pregnant or breastfeed.

• The definition must be stable
  The Court said that having a “variable” definition of “woman” depending on the context or a person’s GRC status would break the legal principle of certainty. People must be able to understand the law by reading it without guessing or checking someone’s private documents.

• Parliament knew what it was doing
  The Scottish Government suggested that Parliament may not have thought about the GRC when it passed the Equality Act. The Court rejected this, saying Parliament was aware of the Gender Recognition Act 2004 and chose not to make GRCs affect the meaning of sex in the Equality Act. So the biological meaning was intentional.

Q: Can you shorten that?

A: The Supreme Court said:

• The Equality Act uses “woman” and “sex” to mean biological sex

• A Gender Recognition Certificate does not change someone’s sex for the purposes of that Act

• Allowing a GRC-based or changing definition would damage the structure and purpose of the law

So trans women, even with GRCs, cannot be counted as women for public board quotas or any other sex-based provision in the Equality Act.

Q: Does this show the UK Supreme Court is politicised or “transphobic”?

A: No. The Court made no political or moral statements about transgender people. It followed normal rules of legal interpretation to decide what Parliament meant when it used the words “woman” and “sex” in the Equality Act 2010. The judges treated it as a legal issue and focused on how to read one statute. They did not try to answer wider social or philosophical questions.

Q: Is the decision fixed for all time?

A: No. Parliament can change the law at any time. If it wants to, it can amend the Equality Act to redefine “sex” or “woman” to include people with a GRC or to follow gender identity more broadly. The Court only interprets the law as it stands. If Parliament changes it, courts will apply the new version.

In short, this moves the issue to the democratic arena. Which is really where it belongs.

Q: Are people likely to overread this in one way or another?

A: Yes. Some will treat the ruling as a broad attack on transgender rights, which it is not. Others will say it is just a narrow technical point, which also isn’t true. It has real consequences for how sex-based rights are applied in the UK.

The decision only affects the Equality Act 2010 but it clearly says that “woman” means biological female within that law. People will probably misunderstand or misrepresent the ruling, either by exaggerating it or downplaying it.

Q: Are New Zealand courts bound to follow this decision?

A: No. New Zealand courts are not bound by UK court rulings. New Zealand has its own legal system.

Q: Could New Zealand courts be influenced by the decision?

A: Yes, they could. Courts sometimes look at decisions from overseas if they deal with similar legal questions and offer helpful reasoning. That is more likely when:

• New Zealand law hasn’t settled the issue

• The overseas law is similar

• The judgment is clear and well reasoned

Q: Is the New Zealand Supreme Court likely to follow the UK Supreme Court?

A: Probably not. New Zealand courts are more willing to change the meaning of a law to match what judges think are current social values. There are limits to this but it has become more common over time.

In theory, judges are supposed to apply widely shared public values. In practice, though, there is no clear or democratic way for them to know what those values are. They don’t take polls, ask the public or defer to elected officials.

Instead, they tend to rely on sources close to their own world, like academics, government agencies, international bodies and favoured interest groups. These sources often reflect the views of the legal and professional class rather than the general public.

So when judges refer to “contemporary values” they often mean their own values and those of their peers. Sometimes these line up with public opinion but not always. The result is that judges can end up reinterpreting the law in ways that don’t match what Parliament actually intended.

Q: Will this ruling actually resolve anything in the ongoing debate over sex and gender?

A: Lol. No.