If you were a poor Muslim girl, the second of 12 children born to an immigrant labourer and an illiterate mother, possessed only of fire, intelligence and a fabulous pair of pins, had scrabbled through racism and gropey misogyny to the pinnacle of French politics, why would you risk everything for such a trifle as a baby?

Rachida Dati, the French Justice Minister, doesn't want to be a poster girl for single mothers or a handy precedent for maternity leave reformers. Rather, by rushing back to the Élysée five days after a Caesarean - to save herself from being reshuffled into oblivion - she might hold on to the bigger prize, her shot at changing the world.

In a tribute to Helen Suzman, the South African politician who died at the new year, her niece recounted how her aunt was impatient with young children and loathed nursing them when they fell ill. When you're an MP single-handedly trying to topple the apartheid regime, whiny, flu-ridden tots must indeed be a bit of a drag. Though these days a Suzman might feel too guilty to leave hot little brows just to make a speech against the pass laws or visit Mandela on Robben Island.

During the boom decade I watched many high-achieving women, one by one, drop out or fall into something lower-ranking and part-time. Some rejoiced in their schoolyard years, others now wonder if they did it only because they felt they should. The work-life-balance brigade, who have successfully made all but the stiffest of employers flexible to family needs, banged its drum too hard at times. Its message, that combining a full-time career and motherhood was mostly unsustainable, hurting not only the tender needs of children but female health and sanity, hit home. Even women coping just fine found themselves wondering: am I crazy, deluded, selfish? If I am lucky enough not to be among the greater millions of women who need to work, what am I doing here? Household calculations were made (wife's salary minus childcare = not a whole lot) desks were cleared, ambitions shelved.

For this was not an age that nurtured ambitious women. Ambitious girls are fine, particularly bosomy ones in tight tops, photographed trouncing the lads on A-level results day. But grown women, powering through corporations or impudently becoming government ministers, are still mostly reviled.

In the signature Eighties movie Working Girl, our humble heroine, Tess, played by Melanie Griffith, uses her smarts and hard graft, endures snobbery and knockbacks, to fight her way out of the typing pool. The film ends with her as a junior executive - an office of her own! - looking out over the glittering possibilities of Manhattan. By contrast, in the recent zeitgeist female career movie The Devil Wears Prada, a resentful and entitled intern Andrea balks at every demand made by her exacting boss. Andrea eventually wins her respect and is offered the keys to her golden kingdom, but, concluding ambition has distorted her true nature, throws them right back.

It should also be noted that on her way up Tess wins her man (and a prime bit of Harrison Ford at that) while Andrea loses hers. To Tess, ambition led to fulfillment and adventure; to the new generation of Andreas it is painted as a soul-destroying fag and a ticket to Lonely Town.

The other day I was interviewed by a 24-year-old Oxford research student who told me she is dismayed by the lack of ambition in her contemporaries. “They worked so hard to get here,” she said. “But I think it was for the prestige. Now they aren't really thinking about careers. I'm not kidding, they just talk about becoming mothers and baking cupcakes.”

I was reminded of this reading how the head of the Girls' Schools Association is worried that footballers' wives - who are wealthy and worshipped without a day slogging the old 9 to 5 - are pernicious role models for young women. Though really you can't blame WAG-wannabes for dreaming, since they are more likely to be facing working lives of low pay and drudgery. But these Oxford girls, what are they thinking? They are of a generation that fought off boys to win a majority of places in medicine, law and accounting, a third in business schools. Yet they hear only the siren call of the cupcake.

It is mostly a myth, the yummy mummy. Few can afford to live in Cath Kidston perfection with candy-coloured Agas. But nonetheless it has become a powerful female aspiration. Idleness has been sold to women as the ultimate freedom. Work - once seen as a liberator from economic dependence and boredom - is portrayed as antithetical to female happiness. Domesticity and motherhood have been repackaged as a destiny as creative, stimulating, satisfying and energy-absorbing as any career.

And it is for some: the woman who doesn't die a little every time she gets out the craft pens or never recalls, when running a stall at the summer fayre, that she once commanded a staff of 20 or doesn't wonder, since she has the better CV, why she is the one balling her husband's socks.

But this myth has led to squandered female potential. Doctors, lawyers, former bankers, women who have acquired such worldliness and wit they could run the country, gather in coffee shops, listlessly shop on the internet, make a meal of a piddling domestic dilemma, waiting for the 3.30pm pick-up when their life will regain its purpose. These women should never have given up their dreams. They stepped on to the “mummy track” or out of work altogether, and mostly they can never, ever get back.

Work is good, it can even be noble. It can make us forget ourselves. That is what we should tell our daughters. It can be hard, thankless, scary, joyless at times. But you will feel useful, purposeful, part of the world. Babies are meant to fit around our lives. We are the only generation in any culture to think the opposite. And I have never detected any difference in happiness, achievement or even good manners between the offspring of working and stay-at-home mothers.

Rachida Dati should be applauded for not giving up, for refusing to be defined by her maternal choices, for not relinquishing power when so many men wish she would. It is the mothers wittering about whether she is bonding with her baby, not Dati, who are selling the sisterhood out. She has a lifetime with her daughter, but this chance will not come again.

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