In the struggle to get enough women into boardroom positions, experts say that bosses have to battle an "unconscious bias", which means their brains are wired to pick people who look like themselves.
You may not think you're prejudiced but science says you might actually be without knowing it, as some people fall into subconscious patterns where they end up appointing people like them as colleagues as they're used to seeing that sort together.
David Cameron was mocked by his cabinet colleague Michael Gove for the "ridiculous" number of old Etonians in his circle, while Vince Cable said that he should try and have more than just four women in his 22-strong cabinet. Even fellow Tory MPs have suggested that he could benefit from unconscious-bias training to avoid a "mini-me" cabinet.
In the latest report into women on boards by the Cranfield School of Management, the authors reported that: "Several organisations said that unconscious bias training is useful in raising awareness about possible gender differences in behaviours that might signal talent during recruitment interviews".
How can you check that you're not suffering an unconscious bias towards men or women? Thanks to Harvard University's Project Implicit, you can test your attitudes in a test which uncovers beliefs "that people are either unwilling or unable to report", like this "Gender-Career IAT" (Implicit Association Test) which reveals how you link men, women with family and careers.
Find out how sexist you might secretly be here.