Scotland’s 2021 census should not ask about ‘legal sex’

National Records of Scotland have commissioned the social research organisation  to undertake further primary research into the guidance that census respondents will receive related to the sex question in Scotland’s 2021 census.

Following NRS’s  that the 2021 census will not present a non-binary sex question, the census will ask:

What is your sex?



However, guidance on how respondents are expected to respond to this question remains unconfirmed. This guidance will determine the meaning of the question and will either capture data related to a person’s lived sex (how a person identifies and is perceived by society) or a person’s ‘legal sex’ (put in single quotation marks as a general definition does not exist in law but most commonly relates to the sex marker on a person’s birth certificate, male or female).

In this blog post I intend to briefly outline some of the major reasons why any move to ask about ‘legal sex’ raises questions as to what is actually meant by this concept, goes against international practice, risks data quality and establishes a dangerous precedent for the collection of other data related to identity characteristics.

What is ‘legal sex’?

A fundamental issue with a ‘legal sex’ question is that there is no general definition of this concept in UK law. Therefore, when we speak about ‘legal sex’ what we are actually speaking about is the sex registered on a person’s current birth certificate.

For the majority of the population, the sex on their birth certificate will match their current sex. However, for some trans and non-binary respondents this will not be the case. Furthermore, among people who have a , and been issued a new birth certificate to reflect their identity, their ‘legal sex’ (birth certificate sex) will match their current sex.

It is also vital to remember that the vast majority of official documents — including passports, driving licenses, bank cards and degree certificates — can be changed without the requirement of a GRC or change to a person’s birth certificate.

We should also pause and remind ourselves of the purpose of census data collection. It is not, as far as I am aware, a national tally of male and female birth certificates. This information will tell us very little. The introduction of a ‘legal sex’ question would mean that, if respondents answer the question ‘correctly’, the ‘female’ and ‘male’ categories would include a diversity of people with very different experiences of living in a sexed/gendered society.

International comparisons

The practice of data collection via a census takes place in countries across the world. It is therefore helpful to position ongoing debates in Scotland against what is taking place elsewhere. As discussed in  (2019), censuses in Australia, Ireland, New Zealand and Canada do not ask about ‘legal sex’. In fact, in Australia and New Zealand the question does not explicitly note that it’s about ‘sex’ and instead asks ‘Is [person name] male or female?’ and ‘Are you male or female?’ When this sample of censuses from comparable, English-speaking countries is considered, the introduction of a ‘legal sex’ question in Scotland would go against international practice and position Scotland’s approach as an international outlier.

Data quality

The census is primarily an exercise in data collection. Although its design is unquestionably shaped by philosophical debates around the meanings of identities, how they are experienced and how they intersect, the census does not define us.

The 2011 census in Scotland advised respondents to answer the sex question according to their lived sex. Prior to 2011, it remains unclear how respondents in Scotland were advised to respond (although in 2001, respondents in England and Wales were also ). However, it can be assumed that, without explicit guidance, people answered the question in the way that they felt best reflected their sex.

Departure from this precedent therefore raises concerns about the potential risks to data quality and the negative impact on longitudinal studies.

A dangerous precedent

Lastly, any move towards asking about ‘legal sex’ takes us down a potentially dangerous path where identity characteristics become anchored to ‘legal’ or ‘official’ documents. For the first time in Scotland, the 2021 census will ask respondents their sexual orientation. Like sex, there is no legal definition for someone being straight/heterosexual, gay or lesbian, bisexual or any other sexual orientation they might identify with. Hate crime legislation, for example,  to people who identify as LGBTQ+ and those who are perceived to be LGBTQ+ (even if they identify as straight/heterosexual). Changing the meaning of the 2021 sex question to focus on a ‘legal’ construct risks opening the flood gates in terms of how we, as a society, recognise identity characteristics more widely.

The census does a lot more than populate a national dataset for researchers and policymakers. It is also an exercise in creating norms for equality monitoring and data collection. In many countries, the collection of census data is the largest exercise conducted by the state (in terms of people involved) and its framing of identity characteristics historically trickle-down throughout wider society. Although these days have perhaps passed, with the census increasingly looking to ‘catch-up’ with work taking place elsewhere, its approach to data collection remains vitally important for everyone’s identities.

 is an equality, diversity and inclusion researcher based in Edinburgh. He is writing in a personal capacity.

Published by Kevin Guyan

Dr Kevin Guyan is a researcher and writer based in Edinburgh whose work explores the intersection of data and identity.

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