The definition of a woman: The legal meaning and practical implications of the Supreme Court ruling

Headlines were made - and both celebrations and protests were staged - when the Supreme Court ruled that the legal definition of a woman under the Equality Act 2010 is based on biological sex. Darren Newman explains the legal background and explores some of the practical implications for organisations.

Whatever controversy it might cause, there is no appeal from a decision of the Supreme Court. The law is whatever the court says that it is. As a result of its decision in For Women Scotland v The Scottish Ministers it is now settled law that for the purposes of the Equality Act 2010 a trans woman remains a man even when she has obtained a gender recognition certificate. Sex under the Equality Act is determined by biology and cannot be changed.

Wide-reaching ruling - narrow facts

For a ruling so profound and sweeping in its scope, the actual facts of the case the court was deciding are rather narrow. Technically, the case is concerned with statutory guidance published by the Scottish Government in relation to the Gender Representation on Public Boards (Scotland) Act 2018. This is an Act of the Scottish Parliament requiring that the non-executive boards of Scottish public authorities (such as Highlands and Islands Enterprise, the National Library of Scotland, Food Standards Scotland and the Crofting Commission) should have the objective that 50% of their membership be made up of women.

In guidance on this issue the Scottish Government said that the appointment of a trans woman with a gender-recognition certificate would go towards meeting this objective. The campaigning group For Women Scotland challenged the legality of that guidance. For reasons that we do not need to go into here, it was accepted that the guidance would only be lawful if the Scottish Government's definition of a woman was in line with that of the Equality Act 2010.

The Scottish Government argued that, under S.9(1) of the Gender Recognition Act 2004, a person who obtains a gender recognition certificate becomes "for all purposes" the sex identified on the certificate. A trans woman might be biologically male, but if she obtained a gender recognition certificate she would legally become a woman.

For Women Scotland successfully relied on S.9(3) of the Gender Recognition Act, which says that S.9(1) is "subject to" the provisions of other enactments. While nothing in the Equality Act expressly disapplies the Gender Recognition Act, the Supreme Court ruled that it does so by implication because anything other than a biological definition of sex would render the Equality Act incoherent and unworkable.

Consistency and predictability of meaning

Central to the Supreme Court's reasoning is an insistence that words like "sex" and "women" must have the same meaning throughout the Equality Act. To hold otherwise, the court said, "would offend against the principle of legal certainty and the need for a meaning which is constant and predictable" (para 175).

For example, S.18 of the Act says that it is discrimination to treat a "woman" unfavourably "because of a pregnancy of hers". But a trans man with a gender recognition certificate may be perfectly capable of becoming pregnant. The Supreme Court held that if S.9(1) of the Gender Recognition Act applied, the trans man would not be able to claim pregnancy discrimination because he would not be a woman. This could not have been the intention of the Act.

The rights of a pregnant man certainly raise interesting questions, but they have little relevance in deciding who should be appointed to the non-executive board of Scottish Water. I am not convinced that it is a good idea to make a ruling of such profound importance on the basis of hypothetical examples.

If the court was dealing with an actual case of a man dismissed for being pregnant they would be able to hear detailed argument on each side and might decide that in such an unusual set of circumstances the definition of "woman" could be given its biological meaning, whereas in other circumstances - such as the membership of public boards - a definition that included those with a gender recognition certificate would be appropriate.

The protected characteristic of sex

The Supreme Court was adamant, however, that if the definition of a woman varied depending on the circumstances, then that would create too much uncertainty. A wide variety of people are placed under duty not to discriminate on the grounds of the protected characteristic of sex and so "it must be possible for sex to be interpreted in a way that is predictable, workable and capable of being consistently understood and applied in practice by this wide range of duty-bearers" (para 152). Employers who have struggled with the definition of disability or philosophical belief may be forgiven for being a bit surprised that it is considered so vital that the scope of a protected characteristic should be so easy to understand.

A stronger point made by the Supreme Court is that it is unreasonable to expect employers to distinguish between trans people who do, and those who do not, have a gender recognition certificate. But if the distinction is an artificial one, it is nevertheless a distinction enshrined in law. The Gender Recognition Act itself says that it is the certificate that operates to change an individual's sex rather than the fact that someone has undergone gender reassignment.

And it is the weight to be given to the Gender Recognition Act that is at the heart of this case. If the provision that someone should be regarded "for all purposes" as having the sex specified on their gender recognition certificate does not apply for the purposes of the Equality Act, then it is likely to be disapplied in other circumstances just as easily.

What to do about toilet provision?

Which brings us, inevitably, to toilet provision. The Equality Act would allow for single-sex toilets - but does not expressly require them. While it is now clear that an employer can prevent a trans woman from using the women's toilets, it is not obvious that the Equality Act means that it must do so.

To tackle that question we must look to the Workplace (Health Safety and Welfare) Regulations 1992, which requires employers to ensure that "separate rooms containing conveniences are provided for men and women except where and so far as each convenience is in a separate room the door of which is capable of being secured from inside" (Reg 20(2)(c)).

Technically the Supreme Court has not ruled on the definition of men and women in these Regulations - but if sex means biological sex for the purposes of the Equality Act, it is difficult to imagine it means something different when it comes to Regulations governing the provision of toilet facilities. Is an employer who allows trans women to use the women's toilets complying with the Regulations? I think we know how the Supreme Court would answer that question.

The legal position may now be clear - but what is less clear is how employers can give effect to it without causing significant distress to some members of their workforce. The Equality Commission is planning to introduce detailed guidance on the application of this decision over the summer. I will be fascinated to see what they come up with.