About [De Bene Esse]

This Latin phrase can roughly be translated as “for what it’s worth”. In law, this phrase refers to proceedings taken to prevent future loss of evidence by the death or absence of a witness, or evidence admitted on a provisional basis without determining its admissibility. The evidence is allowed to stand for the present, subject to future challenges, by then it will stand or fall according to its intrinsic merit and admissibility. This phrase is borrowed here to suggest that the views expressed in this column are provisional, an alternative view for what they’re worth, subject to challenges or disagreement, for no one can claim a monopoly over truth, whereas rational debates and disagreement form the bedrock of a free society.

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The United Kingdom’s Gender Recognition Act 2004 provides that once a person has been issued a gender recognition certificate (GRC), their sex is to be regarded as the acquired gender as stated in the GRC, unless otherwise specified by law.^[1] Recently, the UK Supreme Court held that the term “sex” in the Equality Act 2010 refers exclusively to a person’s biological sex at birth and not the sex acquired under the GRC.^[2] The ruling re-ignited heated debates in society about traditional gender classifications and the rights of transgender individuals. Online discussions were particularly polarised: one side hailing the decision as a victory for biological sex, whilst the other condemning it as a setback for trans rights. What, then, are the actual legal and social implications?

The Supreme Court’s Judgment

The case arose when the Scottish Government sought to improve female representation on public boards by requiring half of the board members be women. However, as trans women (biological males with a GRC) are legally recognised as women under the Gender Recognition Act 2004, it became theoretically possible for a public board to consist entirely of “male” members, namely biological males and trans women. This prompted concerns from women’s advocacy groups. For Women Scotland Ltd brought a legal challenge, arguing that sex-based protection should apply only to those born female. The Scottish Government countered that trans women with GRCs should be treated the same as biological women. The underlying issue—legal recognition of trans identities—has long been a subject of contention.

At the outset, the Supreme Court made clear that it was not addressing moral or policy issues; instead, the case involved solely a technical question of statutory interpretation, namely, whether “sex” in the Equality Act 2010 refers to biological sex or whether it also includes acquired gender.^[3] The Court first reiterated the established principles of statutory interpretation: judges are to ascertain the meaning of words used by Parliament in their context, considering the statutory language as a whole. Background materials, such as Law Commission’s reports or Government’s white papers, may be helpful but they cannot override clear statutory language—especially where that language is unambiguous and does not produce absurd results. These are well-settled principles; but by emphasizing these uncontroversial legal principles, the court made it clear that its judgment was based on technical principles of interpretation rather than controversial value judgments.

Drawing from the statutory language, the legislative context and the legislative history, the Court found that many sex-based protection in the Equality Act—such as those relating to pregnancy and breastfeeding—could only logically apply to biological women. When Parliament enacted the Equality Act in 2010, the Gender Recognition Act was already in existence. Yet, the Equality Act still lists “sex” and “gender reassignment” as distinct protected characteristics, thereby suggesting an intention to differentiate between biological sex and transgender identity.

Furthermore, interpreting “sex” as including an acquired gender will undermine sex-based exceptions in the Equality Act that permit single-sex spaces and services, such as toilets, shelters, or prisons. If trans women (i.e., biological males) are legally considered women in these contexts, they cannot be excluded from such spaces, and this will potentially compromise the privacy and safety for biological women. Such an interpretation, as held by the Court, would contradict the legislative intent. In fact, there are two ongoing cases in the UK that highlight this tension: one involves a trans woman prisoner (biologically male) who was accused to have committed rape against a woman inmate in a female prison;^[4] the other, which is before the Labour Tribunal, involves a female nurse of the NHS refusing to share a changing room with a trans woman doctor.^[5]

The Court also noted that an extended meaning of sex would give rise to uncertainty and incoherence in the day-to-day operation of the Equality Act.^[6] For example, women-only health services providers may find it difficult to determine eligibility: a trans man (biological female) without a GRC may receive a cervical exam, but a trans man with a GRC (and thus legally male) may be excluded, even they look the same in appearance and live their life as a man. Conversely, a trans woman (biological male), who may not be distinguishable in appearance from a biological woman, do not require such services. Service provider may also find it difficult to determine whether it is lawful to offer fertility treatment to a trans male when it is a criminal offence to offer such service for the purpose of assisting a “man” to carry children under the Human Fertilisation and Embryology Act 1990.^[7]

On the other hand, the Scottish Government argued that limiting “sex” to biological sex would strip trans people of equal protection under the law. The Court disagreed.^[8] It held that if a person is discriminated against based on appearance or gender expression—even if they are legally male—they could still claim protection under the Equality Act. In particular, section 19A of the Equality Act, an amendment which was introduced in 2024 on indirect discrimination, provides that a person can claim protection even if they are not a member of the group disadvantaged by a neutral provision. Thus, for example, if a trans woman suffers a disadvantage because of an apparently neutral policy affecting a majority of women, she may still be protected even though she is legally regarded as a male under this judgment.

Discussion

The Court’s decision is well-reasoned and persuasive. From a technical perspective, it is hard to fault the Court’s reasoning. One debatable issue, however, is whether the term “sex” must be interpreted uniformly across the Equality Act. While it is a general assumption that words should be given a consistent meaning within the same statute, courts have previously made exceptions when the context demands otherwise.^[9] In this case, the Court rejected a flexible reading, as it was concerned that this would lead to uncertainties and conflicts with the key provisions in the Act.

The Court started its reasoning with provisions clearly limited to biological sex and proceeded to examine exceptions permitting single-sex arrangements. From there, it concluded that the core provisions of the Equality Act also referred to biological sex. The final step was to consider whether this interpretation deprived trans individuals of protection, concluding that it did not. This sequential reasoning is common and persuasive—but it is not the only possible approach.

An alternative approach begins with the clear and general terms of section 9 of the Gender Recognition Act 2004, which provides that a person’s acquired gender becomes their legal sex “for all purposes”, unless exceptions apply. Under this approach, provisions explicitly referencing biological sex—such as those dealing with pregnancy or breastfeeding—are clearly exceptions rather than the norms; as exceptions, these provisions cannot provide guidance to the interpretation of the other provisions in the Act.

As to the core provisions of protection in the Equality Act, many of the contradictions cited by the Court relate not to the distinction between the biological and the acquired sex, but to the distinction between those with and without a GRC. For example, under the Court’s reasoning, a trans man (biological female) with a GRC will be legally male and ineligible for pregnancy services, whereas a similar person without a GRC will be eligible. Such inconsistencies are clearly inconsistent with the legislative intent and could have been avoided if “sex” is based on biological sex.

This example is however based on a provision that is tied to biology (such as pregnancy). If the provision is not biologically related, such as accommodation in women-only shelters, similar anomalies in the reverse will arise. For example, a trans man who appears fully male may still access women only accommodation, share the same bathroom and shower facilities! Indeed, in this case, if the concern for the acquired gender is that public boards could be constituted entirely by “male” (biological male and trans female), the converse is equally true that they could be constituted entirely by “female” (biological female and trans male). If biological sex is adopted, it could result in an equally absurd situation that a public board with everyone appearing as female (biological females and trans males who are now regarded as females) or male (biological males and trans females who are now regarded as males) could nonetheless be described as a board consisting of half male and half female members.

In short, whether “sex” is interpreted biologically or inclusively to include an acquired gender, some anomalies and contradictions are inevitable. The better approach is to allow flexibility, recognizing the different needs and concerns of individuals of both biological gender and acquired gender in different contexts. Unfortunately, by taking a one-size-fit-all definition, the Court failed to adopt a rights-oriented interpretation; nor did it explore adequately the implications of limiting legal sex to biological sex on transgender individuals’ rights and dignity and the difficulties they encounter in daily life.

From Binary to Neither

By limiting legal “sex” to biological sex, the Court reinforces a binary concept of male and female, placing transgender individuals in a liminal “neither male nor female” space, especially in relation to facilities or spaces designed for single-sex. For instance, a trans woman victim of domestic abuse may be excluded from women-only shelters; a trans woman prisoner may be deemed unsuitable for both male and female prisons. The result is social and legal exclusion.

Admittedly, this isn’t just a legal issue. Trans identity challenges the traditional gender binary, but many services still operate on this classification. Whether the law adopts biological or acquired sex as the legal definition of sex, there remains a need for policy innovation and resource allocation to meet trans individuals’ needs. Some issues are more easily addressed, such as gender-neutral restrooms or unisex changing rooms. Others—such as prison housing or school placement —are far more complex. Even if trans-specific facilities are created, the question remains whether this will inadvertently reinforce segregation of trans people, rather than advancing social inclusion and diversity.

How Should Gender Be Determined?

At its core, the issue is how society defines gender. In the present case, women’s groups fear that trans women may “take up” seats reserved for women, reflecting their view that trans women are not women. This view may stem from prejudice or religious beliefs, but it may also arise from legitimate concerns about personal safety or biological realities. For example, female nurses not wishing to share changing rooms with trans women doctors, or female prisoners unwilling to be placed in the same cell with a trans woman inmate. There is also the question of who trans women police officers may conduct an intimate body search—women or men?^[10] In sports, particularly those requiring physical strength, trans women may enjoy competitive advantages over biological women, raising concerns of fairness. These concerns are not without merits and require tailored responses rather than a one-size-fits-all solution.

How gender is recognised varies. In Hong Kong, while post-operative status is recognised for the purpose of marriage, it is limited to gender by surgical operation. The European Court of Human Rights, however, has held that making sterilisation surgery or treatment which entails a very high probability of sterility a precondition for legal recognition of a person’s transgender status infringes the right to private life under Article 8 of the European Convention of Human Rights.^[11]

The UK requires trans individuals to undergo a formal recognition process before being granted a GRC. Applicants must provide medical evidence from two doctors confirming a diagnosis of gender dysphoria, and evidence that they have been living in their acquired gender for at least two years—such as hormone treatments, official correspondences and bank records reflecting their gender identity.^[12] Obtaining a GRC is not mandatory, meaning that eligible individuals may choose not to apply. The Court noted that this has contributed to confusion: a biological male with a GRC is legally female, but a similar individual without a GRC remains legally male—despite both of them living as women and having female appearances, and yet male sexual anatomy. This makes it genuinely difficult for service providers to distinguish between the sexes.

Some conservatives criticised the UK’s gender recognition process for being too lax, while some more progressive advocates argued that it is too onerous. Some advocates even proposed a self-declaration model, where a person may affirm their gender through a statutory declaration. However, that can risk rendering legal sex effectively meaningless.

Any recognition scheme is ultimately a compromise—and the greater the divergence between biological sex and acquired gender, or the more simplified the recognition process becomes, the harder it will be to achieve widespread social acceptance.

Implications for Hong Kong

As noted above, the UK Supreme Court made clear its decision was a technical legal interpretation of the Equality Act and not a general decision on broader transgender policy. It also stressed that trans individuals retain protection from discrimination—a trans woman harassed at work for appearing as a female is still protected, regardless of her legal sex.

Hong Kong lacks a comprehensive equality statute like the UK’s Equality Act. Its equality protections are found across the Sex Discrimination Ordinance, the Bill of Rights, and the Basic Law. The Sex Discrimination Ordinance does not cover discrimination on the ground of sexual orientation, but the Hong Kong’s Court of Final Appeal has now recognised such discrimination as unconstitutional. Those authorities are unlikely to be affected by the UK decision.

Another area is marriage law. Under current legislation, “marriage” is defined as a union between one man and one woman. In the W case,^[13] the Hong Kong’s Court of Final Appeal ruled that post-surgical operation gender—not biological sex—determines eligibility for marriage. It explicitly rejected reliance on birth-assigned sex. This judgment was partly based on changing social and medical understandings of gender, and this is also unlikely to be influenced by the UK decision. That said, the Hong Kong court stayed its decision for a year to allow the government time to introduce the necessary legislation. Yet the Legislature failed to reach consensus on how to define legal sex. That remains one of the most intractable issues in law and policy.

Civil Partnership

More recently, in the Sham Tsz Kit case,^[14] the Court of Final Appeal affirmed it holding that “the right to marriage” under the Basic Law refers to a union between a man and a woman, and does not include same-sex marriage. As to whether the Basic Law could be interpreted as a living instrument in line with societal changes, the Court did not make any ruling on this point, as Mr. Sham abandoned this argument during the appeal. The Court of Final Appeal also ruled that the absence of a legal framework for the recognition of same-sex partnerships constituted a violation of the right to privacy, and accordingly ordered the Government to enact relevant legislation. The Court further granted a stay of two years for compliance with its ruling.

This two-year deadline will expire on 26 October 2025. However, legislative progress appears to be slow: it was only in early July 2025, barely three months before the expiry of the period of stay, that the Government presented for the first time a discussion paper to the Legislative Council outlining the proposed legislative direction.^[15]

With the view to implementing the decision of the Court of Final Appeal, the HKSAR Government proposed to establish an alternative framework for the legal recognition and protection of same-sex partnerships, while preserving the existing regime of opposite-sex marriage and safeguarding traditional values. A registration mechanism will be introduced to allow eligible same-sex couples to register their partnership.

However, this registration mechanism is only open to those who have validly registered as same-sex partners outside Hong Kong. This effectively means that the Government will only recognise foreign registration of same-sex relationship. For those who, due to financial or other reasons, are unable to travel overseas to register, or otherwise unable to meet the registration requirements of an overseas jurisdiction (such as a minimum period of residency), they will still be denied any legal recognition of their relationships in Hong Kong. This falls short of meeting the requirements set by the Court. A distinction between those who can afford to go overseas for registration and those who cannot may itself contravene the guarantee of equality before the law under the Bill of Rights and the Basic Law.

The rights of the proposed civil partnership are also rather limited. Apart from registration and deregistration, and some provisions relating to access to medical services of one’s civil partner, the proposal makes no reference to the status of any children, natural or adopted, out of the civil partnership or from a previous heterogenous relationship. It also makes no reference to previous court judgments on non-discrimination on the ground of sexual orientation in areas such as housing, spousal benefits in civil service, tax and intestate inheritance. Although the Government has stated that it will continue to implement those judgments, it remains unclear whether those rulings would only apply to registered same-sex couples once the proposed scheme is enacted into law.

Another pre-requisite for registration is that both parties must be of the same sex. This requirement is understandable, given that the legislation is primarily aimed at same-sex couples. However, in determining who may enter into a same-sex partnership, the question of how gender is to be defined will be an unavoidable issue.

At least the HKSAR Government has taken the first step, albeit belated and half-baked, in recognising same-sex relationship. It remains to be seen how the Legislature, which is both compliant and conservative, is going to take it.

Notes:

^[1]* Honorary Professor of Law at University College London and former Chair of Public Law of The University of Hong Kong. I am grateful to my colleague Professor Marco Wan of the University of Hong Kong for his stimulating discussion on this issue. The term “sex” and “gender” are used interchangeably in this article.

Gender Recognition Act 2004, section 9(1): “Where a full gender recognition certificate is issued to a person, the person’s gender becomes for all purposes the acquired gender.”

^[2] Women Scotland Ltd v Scottish Ministers [2025] UKSC 16, paras 1–13.

^[3] Equality Act 2010, section 11: “In this Act, references to a person who has a particular protected characteristic are to a reference to a person of a particular sex, race, etc.”

^[4] “Isla Bryson: What is the transgender prisoners row all about?”, BBC, 28 Feb 2023: https://www.bbc.co.uk/news/uk-scotland-63823420.

^[5] Changing room trans row nurse ‘felt intimidated”, BBC, 3 Feb 2025: https://www.bbc.co.uk/news/articles/cy8p41z972vo

^[6] Judgment, paras 151-161.

^[7] See R(McConnell) v Registrar General for England and Wales [2020] EWCA Civ 599. The Supreme Court found it unnecessary to express a view on this issue in this case: see Judgment, para 108.

^[8] Judgment, paras 142-150.

^[9] Judgment, paras 190-197.

^[10] For example, in Chief Constable of the West Yorkshire Police v A (No 2) [2004] UKHL 21，the Applicant successfully challenged the decision of the Chief Constable refusing to employ here on the ground that she could not conduct intimate body searches against either men or women.

^[11] AP, Garçon and Nicot v France, Applications Nos 79885/12, 52471/13 and 52596/13, Judgment of 6 April 2017.

^[12] For example, in AB v Gender Recognition Panel [2024] EWHC1456 (Fam), the Applicant wanted to achieve a gynaecoid body shape including adult female breast development and also to retain the capacity to have a functional penis, with capacity for erection and genital sexual response. The Transgender Panel considered that there was insufficient evidence to show that she has been living in real life as a female. On judicial review, the court held that the Panel erred in considering only the medical evidence. Instead, it should also all the evidence taken as a whole in considering whether there was a consistent course of conduct in living her life as a female.

^[13] W v Registrar of Marriage (2013) 16 HKCFAR 112.

^[14] Sham Tsz Kit v Secretary for Justice [2023] HKCFA 28.

^[15] https://www.legco.gov.hk/yr2025/chinese/panels/ca/papers/ca20250703cb2-1350-1-c.pdf

 

▌ [De Bene Esse] About the Author

Professor Johannes Chan is an Honorary Professor of University College London and the former Chair of Public Law, The University of Hong Kong.