A hiring model learns from the decisions it is trained on. If past hiring for a role was mostly of one sex, a model can learn to prefer signals that go with that history: certain job titles, hobbies, words or unbroken careers. Other tools score availability, voice or video. The Equality Act 2010 does not ban any of these tools, but it does set the rules they have to meet on sex.
The short answer: sex is a protected characteristic, and a reference to a person who has it is a reference to a man or a woman (s11). An employer must not treat someone less favourably because of sex (s13(1)), and must be able to justify a rule applied to everyone that puts one sex at a particular disadvantage (s19).
The tests
- Direct (section 13): less favourable treatment because of sex cannot be justified (s13(1)-(2)). Less favourable treatment of a woman includes treating her less favourably because she is breast-feeding (s13(6)(a)); where the person is a man, special treatment given to a woman in connection with pregnancy, childbirth or maternity is not taken into account (s13(6)(b)). See direct discrimination.
- Indirect (section 19): a provision, criterion or practice applied to everyone that puts one sex at a particular disadvantage, and the individual at that disadvantage, unless the employer shows it is a proportionate means of achieving a legitimate aim (s19). See indirect discrimination.
- Harassment (section 26): unwanted conduct related to sex, and unwanted conduct of a sexual nature, with the effect set out in section 26 (s26(1)-(2)). See the duty to prevent sexual harassment.
Where AI tools come in
- Models trained on past hiring: where past hires for a role were mostly of one sex, a model can learn to favour signals linked to that group. The employer applying the model is applying a criterion, and if it puts one sex at a particular disadvantage it needs justification.
- Career gaps: penalising gaps in employment can disadvantage people who took time out for childcare or caring. For gaps linked to pregnancy and maternity leave, see pregnancy and maternity.
- Availability and hours: scoring candidates on full availability, unpredictable shifts or long hours can disadvantage people with caring responsibilities. See also flexible working.
- Voice and video scoring: tools that score pitch, tone, "confidence" or appearance can score men and women differently. Ask the vendor how the tool was tested across groups.
- Job adverts and targeting: AI-written adverts with gendered wording, or ad delivery that reaches mostly one sex, can affect who applies.
For pay, including AI job evaluation and pay-setting tools, see equal pay. The employer is responsible for what it does with a vendor's tool.
Practical steps
- Employers: ask what data a model was trained on, turn off gap penalties and availability scores that the job does not need, check advert wording and delivery, monitor outcomes by sex where you lawfully can, and record why each criterion is used.
- Candidates and workers: keep the advert, any score and the rejection, note any question about gaps, availability or family, and ask what criteria were applied.
For time limits and proof, see time limits and the burden of proof; for the Act's other workplace rules, AI and the Equality Act 2010.
This page covers Great Britain and is general information on the law as at 2 November 2026, not legal advice.
Questions and answers
What does sex mean in the Equality Act 2010?
Section 11 says a reference to a person who has the protected characteristic of sex is a reference to a man or to a woman, and people share it if they are of the same sex.
Can an AI tool that penalises career gaps be sex discrimination?
It can be indirect discrimination under section 19 if it puts one sex at a particular disadvantage and the employer cannot show it is a proportionate means of achieving a legitimate aim.
Is treating a woman less favourably because she is breast-feeding sex discrimination?
Yes. Section 13(6)(a) says less favourable treatment of a woman includes less favourable treatment of her because she is breast-feeding.