Women are struggling to get pregnant because they are chasing 'masculine' work goals, a fertility expert has claimed.
Fiona Kacz-Boulton, who appeared at the Fertility Show in London, told an audience that being a breadwinner or pursuing a career could have a harmful biological effect on women's fertility.
According to the Daily Mail, the "natural fertility specialist", who advises doctors and lawyers among other successful clients, said these women have achieved all their ambitions but are unable to have a baby.
She said it is difficult for their bodies to behave in feminine ways if they are acting masculine.
In a speech on how to improve success in IVF, she gave the example of a teacher who was head of her department, with a self-employed husband and significant financial pressure.
Mrs Kacz-Boulton said: "She was the one that had the steady income and she was the one actually wearing the pants in their relationship - and that affects female fertility.
"It is because you are acting masculine and expecting your body to perform in a feminine way."
A fertility conference heard last year that female bankers are 60 per cent less likely to become pregnant through fertility treatment than those of a similar education and income, with women software engineers also struggling.
Stress and a lack of time for fertility appointments were said to play a part.
However Mrs Katz-Boulton, a non-medical specialist, has another theory.
Perhaps controversially, she told an audience: "In this day and age, women are now out working just as much as men, trying to achieve and are in this very masculine state - a yang state, a go-getting state - but then we are expecting our body to be in the feminine state, which is about opening and surrendering (to conceive)."
The founder of firm Awakening Fertility, who claims to have an 80 per cent success rate, tells women to consider changing their jobs or try to manage their stress.
She believes the stress of "masculine" work goals activates the parasympathetic nervous system - which is responsible for the body's 'fight or flight' response.
Experts agree that stress affects fertility, possibly by reducing blood flow in the Fallopian tubes.
Professor Geeta Nargund, medical director of Create Fertility, said: "It is possible that women in a high-pressure environment may be more stressed, which can adversely affect their chances of conceiving.
"But the main thing is for women to maintain a healthy lifestyle. Categorising ambition and drive as masculine is a gender stereotype.
"Women can have both a high-achieving job and a family."
But speaking after her talk at the Olympia exhibition centre in West Kensington, Mrs Kacz-Boulton defended her view that conceiving depends on a proper balance of "masculine" and 'feminine' energy.
The fertility expert, who also advises women to eat organic food, use black-out blinds and perform yoga while trying to conceive, said: "This is a biological fact, it is just society deeming this as sexist.
"The fact is that society is not helping these women, encouraging them to have a career and postpone having kids for as long as possible."