Where sex matters | Data and statistics

Data and statistics

We need accurate data, disaggregated by sex in order to understand differences in the lives of women and men.

Sex is a powerful predictor of almost every dimension of social life including education, employment, crime, physical and mental health. It is difficult to think of an area of life where sex is not an important dimension for analysis.

As Caroline Criado Perez has pointed out, if data is not collected on men and on women then systems – from transportation to medicines and medical devices to tax structures and consumer products – tend to ignore the needs of women, and ”when your big data is corrupted by big silences, the truths you get are half-truths, at best.”

What is the problem?

Increasingly, accurate data collection on sex is being undermined by the conflation of sex, gender and gender identity.

The principle of self-ID has been accepted by many public bodies, replacing sex with self-identified gender when recording crimes and organisational pay gaps, on medical records and in the census.

All three of the UK census authorities (for England and Wales, Scotland and Northern Ireland) had said that they intended to carry guidance to accompany the sex question in the 2021 census that would instruct respondents to answer based on their self-declared gender identity, not on their natal sex or their GRC administrative sex.

Jonathan Portes, former chief economist at the Department for Work and Pensions, said that this would make it much more difficult to track and tackle issues such as the gender pay gap and inequality in childcare, social care, housing and health. There were also legal cases challenging the decision.


  • Why is support for “trans rights” plummeting?

    Why do people think “transgender rights” have gone too far?

    It’s not just about self-ID Support for the law that allows people to change the sex recorded on their birth certificate has fallen a long way over the past few years, most sharply when self-ID was being proposed, in 2018–19 in the UK and then again in 2021–22 in...

    14th June 2024

  • The more people understand the real-world impact of pretending people can change sex, the less they like it

    Another fall in public support for changing sex on birth certificates

    The latest results from the annual British Social Attitudes survey show a further fall in support for the law that allows people to change the sex recorded on their birth certificate. It seems that the more this is talked about, the less people like it. Each year the British...

    12th June 2024

  • What's happening to open government consultations

    Despite the election, you should still respond to consultations

    You can still make a difference by responding: here’s how.

    7th June 2024

  • The government has a chance to sort out the sex data mess

    Getting “sex” right in digital verification services

    The UK government is developing a system for digital verification services (DVSs). The Data Protection and Digital Information Bill which is now at committee stage in the House of Lords is establishing the legal framework for this.  The legislation will lead to the development of a “digital identity and...

    17th April 2024

  • How gender ideology broke the census

    The 2021 census of England and Wales reportedly cost £900m. Amid much fanfare, data on the transgender population was collected for the first time. But the exercise seems to have gone wrong. The question on gender identity may have been misunderstood, giving strange results. The Guardian reported:  “The proportion...

    5th April 2024

  • “The BBC is obliged by its charter to be accurate and without bias” (1)

    Bias at the BBC

    What’s the issue? The BBC’s director of complaints has ruled that the presenter Justin Webb broke the BBC’s rules on impartiality when he commented, in a discussion about a women’s chess tournament on Radio 4’s Today programme, that “trans women” are male. This is shocking behaviour from the BBC:...

    1st March 2024

  • This is not a system error

    An Epic crisis is unfolding in the NHS

    Since October, several NHS trusts in England have been using new £450 million NHS patient-data software produced by US-based IT company Epic Systems. This has been programmed by local teams to record the “gender identity” of babies. For adults, the system has been programmed to register patients according to...

    29th November 2023

  • Where is the harm?

    Putting remembrance in context

    Today, 20th November, is Trans Day of Remembrance, which has been marked annually since 2011 and is intended to commemorate the deaths of trans-identified people caused by transphobia. It has rapidly become a fixture in transactivists’ campaigning calendar. Unevidenced claims about the outsize risks faced by trans people, the...

    20th November 2023

  • The census gender mess

    The ONS should admit its gender-identity question failed

    The Office for National Statistics has released the final summary of its investigations into the quality of the England and Wales census data from the “gender identity” question. A clear assessment of the quality of the data is important, both because the data will be used to drive understanding,...

    8th November 2023

  • Ask a simple question. Expect a simple answer.

    Data matters

    The easiest way to ask about sex is to ask a simple question and expect a straightforward answer. 

    19th October 2023

  • Sex matters in data collection

    Sex matters in data collection webinar

    On 24th October 2023, Sex Matters’ director of advocacy, Helen Joyce, talked with sociologists Michael Biggs and Lucinda Platt about the rights and wrongs of data collection, when it comes to sex and gender identity. Maya Forstater, executive director of Sex Matters introduced a new Sex Matters publication that sets...

    17th October 2023

  • Keep calm and carry on?

    Response to Victor Madrigal-Borloz’s report on the UK

    The UN Independent Expert Victor Madrigal-Borloz has issued an extraordinary report at the end of his ten-day mission to the UK. The thrust of it is the familiar claim that speaking clearly about the material reality of the two sexes amounts to “hate”, alongside the equally familiar dismissal of...

    12th May 2023

  • Thank you, Kishwer Falkner

    We have written to Baroness Kishwer Falkner, Chair of the Equality and Human Rights Commission: Dear Kishwer Falkner Thank you for publishing your letter to the Minister for Women and Equalities setting out, with careful reasoning, why you support revisiting and clarifying the meaning of “sex” as a protected...

    11th April 2023

  • We have come to the view that if ‘sex’ is defined as biological sex for the purposes of EqA, this would bring greater legal clarity in eight areas.

    EHRC publishes letter on clarifying sex in the Equality Act

    Sex Matters’ press statement Sex Matters welcomes the letter from Kishwer Falkner, Chair of the Equality and Human Rights Commission, to Kemi Badenoch, the Minister for Women and Equalities, responding to her request for advice on clarifying the definition of the protected characteristic of sex in the Equality Act...

    4th April 2023

  • What did we learn from the census?

    Key points The questions In 2021 the census for England and Wales included a voluntary question on gender identity for those aged 16 years and over. There was also a mandatory sex question which sought to collect information on people’s sex, which was clarified in court by Fair Play...

    31st January 2023

  • Sex Matters in the Media webinar

    On Thursday 26th January at 7.30pm, our director of advocacy, Helen Joyce, talked to communications consultant Conrad Roeber about the media’s failures in reporting on sex and gender, and what readers and viewers can do to make things better. They discussed the Sex Matters Media handbook, our guide for...

    18th January 2023

  • Risks in the final rush to legislate self-ID in Scotland

    The Scottish government’s plans to allow anyone from age 16 upwards who is ordinarily resident in Scotland to obtain a gender recognition certificate (GRC) without any medical assessment are due to be voted on by the Scottish Parliament tomorrow, 21st December. The vote comes barely a week after the...

    20th December 2022

  • Clarify the Equality Act: sign the petition

    The Equality Act 2010 protects everyone’s rights and covers everything from schools to hospitals, pubs to sports, and everybody’s workplace. It includes protection against sex-discrimination, and allows single-sex services. But on 13th December a judge in Scotland pronounced that Equality Act does not recognise biological sex as a protected...

    16th December 2022

  • UCAS’s plan will make this already bad situation worse.

    Why we have written to UCAS about data

    The latest attempt to destroy data on sex by replacing it with data on self-declared “gender identity” is in the higher-education system. The Universities and Colleges Admissions Service (UCAS), the national undergraduate admissions service that acts as gatekeeper to all university places, is planning to change an already-flawed question...

    7th December 2022

  • Campaign update: Day 1

    Yesterday we launched the Make the Equality Act Clear petition, calling on the government to clarify, with a legislative amendment, that sex means sex in the Equality Act 2010. It got an amazing response. In less than 24 hours, 15,000 people signed the petition, and the number is continuing...

    3rd November 2022

  • "We recommend the simplest, clearest, most neutral and most coherent approach reporting based on sex."

    Sex Matters’ advice to companies on the FCA’s new reporting requirements

    Last week, we reported that the Financial Conduct Authority had issued new rules about its requirements for listed companies to report on the proportion of women on corporate boards, scrapping its earlier proposal for this to be based purely on gender self-identification. The new regulations let companies choose whether to report...

    29th April 2022

  • Financial regulator scraps self-ID plan

    Financial Conduct Authority says corporate boards can use sex not gender

    The Financial Conduct Authority has issued new rules requiring listed companies to report on the proportion of women on corporate boards, scrapping its earlier proposal to require this to be based on gender self-identification. 439 people and organisations (over 80% of respondents) raised the issue of gender vs sex...

    20th April 2022

  • Sex in the Census: Reality v Paperwork

    The Outer House of the Court of Session in Scotland handed down judgment last week in Fair Play For Women’s challenge to guidance on the census. National Records Scotland plans to tell members of the public that if they are transgender, they can choose how to answer the sex question. ...

    22nd February 2022

  • “How digital identities can solve the problem with sex and gender identity – and how getting it wrong will make the problem worse.”

    A radically simpler system than gender self-ID

    Critics of the Gender Recognition Act who call for gender self-identification say the current system is too much of an administrative burden. They are calling on the government to bring people together to find solutions.

    21st February 2022

  • Do crime victims deserve respect?

    We think crime victims deserve respect, dignity, sensitivity, compassion and courtesy, as specified in the Victims’ Code.

    10th February 2022

  • Getting it right: diversity and inclusion

    The business risk of misaligned D&I

    Sex Matters in the City

    16th December 2021

  • X passports appeal dismissed

    The Supreme Court has unanimously dismissed Christie Elan-Cane’s case for an “X” passport. The judgment states  “There is no judgment of the European Court of Human Rights which establishes a positive obligation to recognise a gender category other than male or female, and none which would require the Secretary...

    15th December 2021

  • No need for sex data on domestic abuse?

    Yesterday the Domestic Abuse Commissioner launched a survey for survivors of domestic abuse about their experience of using domestic abuse services across England and Wales: “We are running this survey so that we can understand what is good about domestic abuse services in different areas of the country, and...

    7th December 2021

  • Sex matters in the City

    The Financial Conduct Authority is the regulator for the financial services sector in the UK. They are proposing to set new rules to encourage big companies to have more “female” directors on their boards. The new regulations would cover over 1000 firms, employing tens of millions of people, and...

    19th October 2021

  • Fighting for the principle of collecting data on biological sex

    A guest post by MurrayBlackburnMackenzie. Scottish Parliament Public Petition: Call for signatures In early June MurrayBlackburnMackenzie (MBM) lodged a petition with the Scottish Parliament Public Petitions Committee. It calls on the Scottish government to require Police Scotland to accurately record the sex of people charged or convicted of rape...

    27th June 2021

  • Truth and reconciliation

    How should the public sector leave the Stonewall Champions Scheme?

    6th June 2021

  • Time to #LeaveStonewall

    This is the letter we have sent to the CEOs of the 850 organisations that are members of the Stonewall Diversity Champions Scheme. Re: Leaving the Stonewall Diversity Champions Scheme We are writing to call on you to withdraw from the scheme, both for the sake of your own...

    29th May 2021

  • Sex, gender and medical data: a way forward

    Susan Bewley, Margaret McCartney, Catherine Meads and Amy Rogers published an article in the British Medical Journal calling for clarity about sex and gender in medical records and data.

    This a "rapid response" from Sex Matters co-founder Maya Forstater that was published online by the BMJ.

    23rd March 2021

  • NHS: let’s talk about sex

    This tweet by Emma Parnell, Lead Service Designer at NHS Digital and the associated Medium post “Lets Talk About Sex” is interesting. Parnell writes in detail about how she worked to remove the question of whether a patient is male or female from the online system for booking COVID...

    20th March 2021

  • Sex (or gender?) as a hate crime: why the rush?

    The push to adopt a gender neutral definition of “misogyny” as a hate crime with amendment 87B to the Domestic Abuse Bill (being debated this afternoon in the House of Lords) is another attempt at the political erasure of sex. Why the rush when the Law Commission is working...

    17th March 2021

  • Census guidance on the sex question ruled unlawful

    Census day is 21 March 2021. Yesterday, in a challenge brought by Fair Play For Women, the High Court ordered the Office for National Statistics to correct the guidance they provide online about how to answer the question “What is your sex?”   Until yesterday, the guidance for the 2021...

    10th March 2021

  • ONS reverses decision to ask clear sex question on the census

    The ONS has reversed its decision not to allow self-identified answers to the sex question in next month’s Census. On 22 January, 2021 The UK’s Chief Statistician, Professor Ian Diamond, confirmed on BBC Radio 4’s Today program the question “what is your sex” should be answered according to someone’s LEGAL SEX,...

    12th February 2021

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