This week, the British Labour Party's deputy leader suggested that women are seen as "past it" once they have a baby, essentially written off as distracted and too family-oriented to make good employees. By the time they manage to turn that stereotype around, they've missed the boat at work.

Here's how Harriet Harman bluntly put it in Grazia Magazine, as the Telegraph reports: "you're too young; then with children, an absolute write off, too much on your plate; and then past it. You never have a prime. Yet for men when they're young they're ambitious and thrusting: if a man has four children, his work colleagues will regard him as reassuringly virile. And then when he's older, he's all wisdom and sagacity."

A new article in Reader's Digest also suggests there is a persistent discrimination against new moms in Canada – especially when they take advantage of the year-long maternity-leave policy introduced by the Liberals more than a decade ago. In addition to citing lawyers that handle numerous parent-leave cases each year, the piece also tells the story of Kendra Schumacher, an experienced art director who took time off after training a replacement for her job. Before she returned, her replacement was replaced by a stranger who stayed on – and, she says, her job responsibilities were downgraded. When she asked about her boss' long term plans for her, she says he told her: "There are none." She found a new job rather than raise a fuss.

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Canada's maternity-leave policy – often cited as a model for other countries – requires that women return to their original jobs (or a comparable position) when they come back to work, except in vaguely defined "exceptional circumstances." But one lawyer interviewed suggested some employers were using that as a loophole, sometimes to demote or even fire new mothers, who may return to workplaces and find their skills are out of date, the workplace environments have changed or a younger person (sans kid) is just doing the job better, and without distractions at home.

And let's face it: There's nothing like a sudden fever, case of lice or call from daycare to complicate your workday. But, especially as dads are increasingly likely to be making the emergency dash out the office door, that's doesn't mean moms aren't pulling their weight. And if anything – given the rising trends in female education – it means employers better adjust their attitudes.

Even as Ms. Harman notes the long-standing mommy bias, her own career suggests that she eventually recovered herself – after all, at 62 she is the deputy leader, and by her own account "in my prime" now that her kids are adults. But then most women would probably rather not have to wait around for 18 years to advance in their careers.

Is there a bias against moms in the workplace? Or with more dads stepping up, is that changing?