“Sex” is a protected characteristic – but what does “sex” mean? The author explains the likely options as a matter of law, and the implications for provision of services, particularly to transsexuals


Terms such as “transsexual”, “gender” and “gender reassignment” are used as they appear in the relevant legislation. Their usage here does not imply their fitness for current non-legal discussion.


The law remains sexed. Although formal rules (statutory and common law) which incorporated and enforced patriarchal notions as to the proper roles of men and women in society have largely or completely gone, the measures enacted to prohibit sex discrimination in wider society (together with the exceptions thereto) necessarily require a legally recognised or constructed concept of sex. Prohibitions of discrimination on the grounds of sex, sexual orientation or trans-status cannot operate without some notion of sex. However, there is no statutory definition of “sex”, or of “male” or “female”.

A lawyer cannot help but wonder, what is sex? And what implications does that have for equality law?

Sex at common law

At common law, sex was fixed according to a person's chromosomes and endogenous sex organs (internal and external), assuming these were congruent. Only otherwise would psychological considerations be relevant (Corbett v Corbett [1971] P 83, followed by R v Tan [1983] QB 1053 and Bellinger v Bellinger [2003] 2 AC 467). This was first addressed in 1971 in the context of marriage, but came to be assumed also to hold for all legal provisions distinguishing between men and women (A v Chief Constable of West Yorkshire Police [2005] 1 AC 51, para 30 per Lady Hale).

Sex and equality law before 2004

Before the Gender Recognition Act 2004, domestic law admitted of only one real exception to the immutability of sex, in the field of equality law. A v Chief Constable of West Yorkshire Police [2005] 1 AC 51 concerned a statutory requirement that a detainee be searched by a police officer of the same sex. The police force refused the application of a trans person (who had undergone surgery and hormonal treatment) to become a police officer, as it would be inappropriate or unlawful for that person to search either males or females. The House of Lords held in favour of the applicant, with two similar rationes decidendi, that the relevant EU directive required that a person should be regarded as a member of the sex with which one identified where that person:

  • was “visually and for all practical purposes indistinguishable” from those who were born of that sex (Lords Bingham, Steyn and Carswell: paras 11, 15, 64); or
  • had “done everything that… possibly could [be done]… to align… physical identity with… psychological identity… [and had] taken the appropriate hormone treatment and concluded a programme of surgery”  (Lord Steyn, Lady Hale, Lord Carswell: paras 15, 61, 64).

In my view, it is questionable whether the West Yorkshire Police decision remains of much relevance. The events giving rise to the proceedings predated amendments to the Sex Discrimination Act 1975 by the Sex Discrimination (Gender Reassignment) Regulations 1999 (SI 1999/1102) (see West Yorkshire Police, para 17), and the decision itself predated the passing of the Gender Recognition Act 2004. Lady Hale stated: “Until the matter is resolved by legislation, there will of course be questions of demarcation and definition. Some of these… will be sensitive and difficult… The Gender Recognition Bill provides a definition and a mechanism for resolving these demarcation questions” (para 60).

And as West Yorkshire Police was decided in favour of the applicant, it could only ever have been an authority on what was sufficient to achieve a change in sex for the purposes of equality law, not what was necessary.

Now that the national authorities have legislated, it is to that legislation we must look, in the absence of any suggestion of incompatibility with EU law or post-Brexit “retained” EU law (European Union (Withdrawal) Act 2018, ss 4, 6(7)). Importantly, the obligation under EU law concerns only “the result to be achieved”, leaving to “national authorities the choice of form and methods” (Treaty on the Functioning of the European Union, art 288). Thus, it does not matter whether adequate protection is secured by national law for trans persons through how sex is defined in law, or through other legislative techniques.

(I have not overlooked Croft v Royal Mail Group plc [2003] ICR 1425. That also predated the 2004 Act, but was not mentioned by the Law Lords in the later West Yorkshire Police decision. Given their silence, I omit further comment.)

Gender Recognition Act 2004

The 2004 Act entitles person aged 18 years or older, on application, to be granted a gender recognition certificate (“GRC”), where the applicant has or had gender dysphoria, “has lived in the acquired gender” for two years, and “intends to continue to live in the acquired gender until death” (ss 1, 2). There is no requirement to undergo any surgical or hormonal treatment. Upon the issue of a GRC, “the person's gender becomes for all purposes the acquired gender (so that, if the acquired gender is the male gender, the person's sex becomes that of a man and, if it is the female gender, the person's sex becomes that of a woman)” (s 9). But despite this change applying “for all purposes”, it “does not affect” a person's status as mother or father of a child (s 12), or their entitlement to a hereditary peerage (s 16).

Equality Act 2010

The Equality Act 2010 sets out several “protected characteristics” in respect of which discrimination of various kinds is prohibited in certain fields of activity.

The 2010 Act provides that: “a reference to a person who has a particular protected characteristic [relating to sex] is a reference to a man or to a woman” (s 11). “Man” and “woman” mean respectively a “male” or “female” of any age (s 212(1)); male and female are not defined. The Act further provides that the protected characteristic of sexual orientation concerns “sexual orientation towards – (a) persons of the same sex, (b) persons of the opposite sex, or (c) persons of either sex” (s 12).

Regarding those the Act dubs as “transsexual”, it provides: “A person has the protected characteristic of gender reassignment if the person is proposing to undergo, is undergoing or has undergone a process (or part of a process) for the purpose of reassigning the person's sex by changing physiological or other attributes of sex” (s 7).

Exceptions from the prohibitions of sex and gender reassignment discrimination exist with respect to the provision of services, provided the different treatment is a “proportionate means of achieving a legitimate aim” (sched 3, paras 26-28).

For sex discrimination, this is permitted inter alia where: separate services are provided “for persons of each sex” if a joint service for persons of both sexes would be “less effective” (sched 3, para 26); and provision “only to persons of one sex” is permissible where:

  • “only persons of that sex have need of the service”;
  • the service is provided at a hospital or other establishment for “persons requiring special care, supervision or attention”; or,
  • the service will be used at the same time by multiple people, or involve physical contact between the provider and user of the service, and the presence of or contact with a service user of the other sex “might reasonably [be] object[ed]” to (sched 3, para 27).

The exception to the prohibition of gender reassignment discrimination is tied into the provision of separate, different, or sole provision of services for “persons of one sex” (sched 3, para 28).

The exclusion of members of the opposite sex is also permitted from single-sex educational institutions; there is no equivalent exception for discrimination on the ground of gender reassignment. An institution is “single-sex” if it admits pupils or students of “one sex only”, disregarding those whose admission is “exceptional” or is confined to “comparatively small numbers” admitted to “particular courses or classes” (sched 11, para 1; sched 12, para 1). 

The meaning of sex

What then does the 2010 Act mean by sex? There appear to be four arguable possibilities.  Three would be based on the common law notion of sex, as the default, subject to modification for trans persons. The three possibilities arise from what is used to demarcate trans status, either: (i) holding a GRC; (ii) being “for all practical purposes” indistinguishable from or having done everything possible to align with the identified sex (West Yorkshire Police); or (iii) being transsexuals in the sense of s 7 of the 2010 Act. The final possibility would simply be based on the common law without any exception – i.e. on the basis that sex was immutable.

I have already said why I think the second possibility, based on West Yorkshire Police, ought to be discounted, given that it constitutes an attempt by the House of Lords to fashion a rule to ensure the observance of EU law in the absence of legislation by Parliament. Given the process to change legal sex created by the 2004 Act (for which neither surgical nor hormonal treatment is a prerequisite), and the protection offered by the 2010 Act against gender reassignment discrimination which applies both to current GRC holders and those simply proposing to undergo “gender reassignment”, there is simply not the same need to graft an extra-statutory category of trans person onto the common law notions of male and female.

The third possibility should also, I suggest, be discounted. Transsexuals are defined in s 7 of the 2010 Act as persons possessing a “protected characteristic”, so that if they suffer discrimination as persons possessing that protected characteristic (i.e. as transsexuals), they are protected by the Act. Section 7 does not deem them to be of the sex they identify (or propose to identify) with or as. If it did, those proposing reassignment but yet to embark upon it would immediately cease to be treated as members of their original legal sex and automatically be regarded as members of the sex of their intended identification. Their proposal to reassign would be enough, for instance, to secure admission of a male child to a girls' school, or to permit the exclusion of a female child from a girls' school.

The first possibility is perhaps the most superficially appealing to a lawyer. Given that the Gender Recognition Act 2004 is to effect a change in gender “for all purposes”, that certain fields are specified where the change is to have no effect, and that equality law and fields such as education and single-sex services are not so specified, the contention that once one's sex changes in terms of the 2004 Act it also does so for the purposes of the 2010 Act is attractive.

However, it throws up certain difficulties which make this conclusion far from certain. Because a lawyer would normally expect the same term to mean the same thing when used throughout the same Act. Where “sex” is used in the Act to describe the object of sexual orientation (s 7), it must be describing something closer to the notion of sex at common law simpliciter, rather than sex subject to the Gender Recognition Act 2004. Sexual orientation concerns attraction to sexed attributes, rather than a legal status. And whether sexual orientation is concerned with attraction to members of one sex by reason of one's belief of them being of that sex (K Stock, “XIV – Sexual Orientation: What Is It?”, Proceedings of the Aristotelian Society, Vol 119, Issue 3 (October 2019), 295-319), or attraction merely to the apparent physical attributes of that sex, a person does not become or cease to be the potential object of attraction from any given person because of being granted a GRC. Further, reference in the exceptions for single-sex services to services which only one sex has “need” of makes more sense if it is referring to sex in a physical and/or physiological sense. I find it difficult to conceive of any need that arises which is common to both GRC holders who have acquired one particular sex, and original members of that same sex, but not members of the opposite sex.

I therefore suggest that where “sex” is used in the 2010 Act, there are two real possibilities. First, that sex is meant in the immutable, common law sense. Alternatively, it is meant in the common law sense except for those who hold a GRC. I do not think either possibility can be dismissed.


This has important implications both for the education and the provision of services.

A transsexual male child who is refused admission by an exclusively all-girls school, which admits of no exceptions, is not treated less favourably on the grounds of gender reassignment. That child is protected against less favourable treatment because of that protected characteristic (i.e. being transsexual). That person’s sex according to law is unaffected. That person cannot be compared to a non-transsexual girl, because the person being denied admission is not legally a girl. That person is treated no worse than a non-transsexual boy. Thus, the less favourable treatment is on account of sex, not gender reassignment. The single-sex school has no obligation to admit that child.

The point is clearer with sex-segregated and single-sex services (at least with those without a GRC). If persons of the other sex are admitted, they cease to be services segregated or exclusive on the basis of sex, and thus lose their exception from the obligations not to discriminate because of sex. The explicit provision allowing single-sex educational institutions to admit some members of the opposite sex tells against any such possibility being implied with the provision of sex-segregated or single-sex services. That being so, the exclusion of trans persons legally of the opposite sex is not simply permissible but a necessary part of the statutory scheme. There is no need to invoke the exception for gender reassignment discrimination (sched 3, para 28), because they are not being treated differently because of their transsexual status.

On this view, that exception for gender reassignment discrimination with single-sex or sex-segregated services is designed to cater for either or both of the following:

  • If GRC holders are regarded under the Equality Act 2010 as having the sex they have legally acquired, it potentially permits the exclusion of GRC holders from services for that sex (e.g. exclusion of male-to-female GRC holders from female services).
  • In any event, it potentially permits the exclusion of transsexuals from services for their original sex, perhaps where they have undergone a physical process of reassignment to such an extent as to make their use of that service problematic (e.g. exclusion of female-to-male transsexuals from female services).

Justifications for transsexual discrimination

On any view, what standard would be required for exclusion of transsexuals from single-sex services? In my view, the exception for gender reassignment discrimination should be interpreted in a manner consistent with the exceptions for sex discrimination. It follows, in my view, that the standard should not be assumed to be any higher than that required for excluding, for instance, men from female wards in hospitals, and the like. If, contrary to my view, all transsexuals (in the 2010 Act sense) are to be regarded for the purposes of equality law as the sex they identify with, the reasons for excluding them as a class will be the same or similar as for excluding those of their original sex.

And the proportionality of the justification could be assessed on a class, rather than an individual, basis. Just as one does not require evidence that a particular man’s behaviour or physical strength or inclinations made his presence in a female ward unacceptable, similarly justification for excluding some of those with the characteristic of gender reassignment might be done on the basis of some general criterion.


Reform of the regime under the Gender Recognition Act 2004 is currently under consideration on both sides of the border (consultation on a draft bill for Scotland is currently open, until 17 March 2020). But before we change the law, we ought to understand what effect the current Act has. All we can be sure of at present is the importance of sex, if not the meaning.



The Author

Julius Komorowski is an advocate with Terra Firma Chambers

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