Is your ‘gender’ data still suitable for pay gap reporting?
28th September 2026
Samantha Gee
A significant change to UK gender pay gap reporting guidance appears to have gone relatively unnoticed.
From 21 May 2026, Government guidance makes clear that statutory gender pay gap calculations must be based on employees’ biological sex, rather than gender identity.
For many employers, that creates an immediate practical issue.
What has changed?
The Gender Pay Gap Regulations themselves have not been rewritten. They continue to require employers to compare the pay of male and female employees.
However, following the Supreme Court judgment on the meaning of ‘sex’ in the Equality Act 2010, the Government updated its statutory gender pay gap guidance in May 2026.
The guidance now states that:
- ‘gender pay gap reporting must be based on employees’ biological sex.’
This is therefore a mandatory change to the reporting approach.
Do you hold the right data?
This is where I think many employers may have a problem.
Over recent years, many HR systems have used a single field labelled ‘gender’, often allowing employees to record their gender identity. In some organisations, this may be the only information held.
Such data cannot automatically be assumed to represent biological sex for the purposes of statutory gender pay gap reporting.
The updated Government guidance says that where employers do not hold the required data, they should take reasonable and proportionate steps to obtain it and recommends having a consistent policy or process for doing so.
Obviously, employers should not single out individual employees. Where existing records are unreliable, employees could instead be invited confidentially to check or update their records.
Importantly, the guidance does not recommend asking employees to provide documentation proving their biological sex.
What about employees with a Gender Recognition Certificate?
The guidance is also explicit on this point.
For gender pay gap reporting, an employee with a Gender Recognition Certificate (GRC) should be included according to their biological sex, rather than the acquired gender recorded on their GRC.
This is particularly sensitive information, and employers need appropriate confidentiality controls. The Government specifically highlights the need to minimise access and avoid inadvertent disclosure of an employee’s pre-GRC gender.
What should employers do now?
Before the next gender pay gap reporting cycle in 2027, we recommend employers:
- check exactly what the ‘gender’ or ‘sex’ field in their HR system actually records
- establish whether the data can reliably be used as biological sex for statutory reporting
- consider two fields going forward to reflect biological sex and gender
- review employee data collection and privacy notices
- establish a confidential and consistent process for correcting or confirming data where necessary
- ensure access to particularly sensitive information is appropriately restricted
- document the methodology used for the gender pay gap calculation
With the next snapshot date approaching, this is worth addressing now rather than discovering during the calculation that the data required for statutory reporting is not accurately available.
How we can help
At Verditer, we support employers with gender pay gap calculations, reporting, narratives and action planning. If you are unsure whether your current employee data meets the new requirements, please get in touch.
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