Introduction

The case of Castellucci, R (On the Application Of) v Gender Recognition Panel & Anor ([2025] EWCA Civ 167) presents significant questions on the interpretation of the Gender Recognition Act 2004 (“GRA”) in light of foreign-acquired non-binary gender status. The appellant, identified as non-binary and having legally acquired this status in California, challenged the panel’s decision to record their gender as the binary “female” on a Gender Recognition Certificate (GRC).

The core issues centre on whether the GRA permits the recognition of a non-binary gender acquired abroad under Section 1(1)(b) and 1(2)(b) and, if it does not, whether such an interpretation conflicts with Article 14 of the European Convention on Human Rights (ECHR) when coupled with Article 8. Furthermore, the appellant questioned whether an interpretation compatible with evolving social understandings of gender could be created under the strong interpretative obligations of the Human Rights Act 1998, or whether a declaration of incompatibility would be necessary.

The dispute involves complex interactions between domestic statutory interpretation, the rights of individuals undergoing gender transition—including non-binary identities—and international human rights norms. The appeal follows previous decisions at the Divisional Court and addresses both statutory and European Convention dimensions.

Summary of the Judgment

The Court of Appeal ultimately dismissed the appeal, upholding the decisions of the Divisional Court. The judgment confirms that under the ordinary construction of the GRA, a person’s acquired gender—when obtained through the foreign law route—is confined to the binary categories of “male” or “female.” Even though the appellant had acquired a legally recognized non-binary status in California, the Court held that this does not extend to recognition in the United Kingdom.

The court rejected the appellant’s arguments that a literal interpretation of the term “gender” should embrace a non-binary concept or that the GRA should be reinterpreted to conform with contemporary approaches to gender diversity. It also found that the Government has provided sufficient objective justification for maintaining the binary framework, largely on the grounds of administrative coherence, significant cost implications in overhauling current systems, and the absence of a consensus internationally.

Furthermore, the Court dismissed the claim that the current statutory framework is incompatible with Article 14 of the ECHR. Even though the appellant had experienced demonstrable practical difficulties, the differential treatment was found to be objectively justified under the proportionality test applied by the Court.

Analysis

Precedents Cited

The judgment extensively discusses both domestic and international precedents. Notable precedents include:

• Goodwin v United Kingdom: This case was seminal in establishing the need to protect transsexual individuals’ rights under the ECHR. Its influence is apparent in the structure of the GRA, which sought to remedy previous incompatibilities.
• Bellinger v Bellinger: The House of Lords’ decision in this case underscored the significance of biological determinacy in gender recognition. The Court of Appeal in the present judgment cited this to justify that official records should reflect a binary categorisation.
• R v Wimbledon Justices, ex parte Derwent and R v Oakes: These cases were invoked to reinforce the principle that courts must adhere to the statutory text without reading extraneous meanings into the legislative language.
• Assange v Swedish Prosecution Authority: The discussion here helps illustrate that while words used in legislation may have multiple meanings in different contexts, the presumption of a consistent meaning across a statute remains persuasive.
• Elan-Cane: Particularly influential, this decision clarified that the balance between effective administration, social policy, and the rights under the ECHR must be maintained. Lord Reed’s observations about the margin of appreciation and the need for international consensus reinforced the Court’s decision to uphold the binary approach.

Legal Reasoning

The central legal reasoning in the judgment revolves around statutory interpretation and the balance between literal and purposive readings. The Court rejected the appellant’s submission that a purely literal reading of the GRA should automatically incorporate a non-binary recognition. Instead, it emphasized the modern interpretative approach, which requires contextual reading and must give effect to the legislative scheme as a whole.

The Court noted that while the appellant’s acquired status of non-binary gender in California is uncontroversial under California law, the GRA’s framework explicitly refers to “either gender” in a binary fashion. Section 9(1) of the GRA was particularly critical, as its phrasing—the absence of qualifying language like “for example”—makes it clear that, upon issuance of a GRC, a person’s gender legally becomes that of either a man or a woman.

Mr Chris Buttler KC’s argument that international comity and the principle established in remedies concerning foreign-acquired statuses (e.g. polygamy or civil partnerships from other jurisdictions) should extend to non-binary recognition was also carefully considered and ultimately found unpersuasive. The Court emphasized that any radical reinterpretation of the statute would amount to a change in the law that Parliament has not enacted, and therefore should be left to the legislative process.

Impact on Future Cases and the Relevant Area of Law

The decision reinforces the binary framework of the GRA, thereby limiting the scope for including non-binary gender recognition via the foreign law route. In practice, this means that applicants who have acquired a non-binary status under a foreign regime will continue to face administrative challenges and may be compelled to choose between the categories “male” or “female” when engaging with UK documentation and processes.

Administratively, the ruling is significant. It preserves the legal and operational coherence of public services such as the issuance of passports, biometric residence permits, and driving licenses, all of which are structured around a binary concept of gender. At the same time, the judgment leaves open the possibility for future legislative reform. The Court clearly indicates that if Parliament wishes to reflect modern understandings of gender—including non-binary recognition—it must do so through explicit statutory amendments following thorough consultation.

Complex Concepts Simplified

Several legal concepts in the judgment are complex; the following explanations help clarify them:

• Acquired Gender: In the context of the GRA, this term refers to the gender a person has legally adopted via either the domestic or foreign route. Under domestic law, this is confined to the binary categories. The Court held that even if foreign law recognises a non-binary gender, the UK’s statutory scheme does not.
• Margin of Appreciation: This principle, often cited in human rights jurisprudence, acknowledges that national authorities have a degree of discretion in balancing individual rights against broader social or administrative concerns. Here, it supported the state's decision to maintain a binary system.
• Literal vs. Contextual Interpretation: While a literal reading of a text focuses on the plain meaning of the words, a contextual reading considers the purpose of the legislation and the broader statutory framework. The Court found that the GRA’s overall legislative purpose was not to extend gender recognition beyond the binary even if foreign jurisdictions might differ.
• Declaration of Incompatibility: Under the Human Rights Act 1998, if a court finds that a statute is incompatible with the ECHR, it can issue a declaration. However, in this case, as the Court held the GRA was consistent with the Convention rights under a proportionality analysis, no such declaration was necessary.

Conclusion

The Court of Appeal’s decision in Castellucci v Gender Recognition Panel reaffirms the interpretation of the GRA within a binary framework. Despite the appellant’s well-documented journey and the recognized non-binary status under foreign law, the judgment underscores that the current UK legal scheme confines gender recognition to the categories of “male” and “female.”

The reasoning highlights a cautious, context-sensitive approach to statutory interpretation. The decision places significant emphasis on maintaining consistency across administrative systems and respecting the limitations set by Parliament. Moreover, the analysis of proportionality under Article 14 of the ECHR reveals that the differentiation is objectively justified given the broad implications for public services and social policy.

Ultimately, while the ruling leaves the door open for future legislative changes, it makes clear that any expansion of recognition to include non-binary identities must come from Parliament—not the judiciary. The judgment is thus significant in setting a firm precedent for how foreign-acquired gender statuses are treated under UK law, ensuring legal certainty and administrative coherence while acknowledging that broader social changes require a democratic process.