Not long ago, a former intern of mine called me to share some exciting news: she'd just landed her first real journalism job. She had plenty of reason to be amped up—jobs in our industry are hard to come by, and entry-level gigs are especially competitive. We have a candid relationship, so I asked her how much she'd been offered as her starting salary.

$40,000, she told me—barely enough to scratch by in New York, even with roommates and George Foreman grilled cheese for dinner every night.

When I suggested she ask for even $3,000 more, the young woman looked horrified.

I can't, I mean, what if they rescind the offer?

Her response perfectly encapsulates the irrational, worst-case-scenario mindset that often cripples women at work. Too many of us simply accept job offers without any back and forth over salary, benefits or perks. This though several studies show men tend to negotiate their job offers, and, not surprisingly, end up outearning women even right out of college. The consequences of restraint are costly: one study by Linda Babcock and Sara Laschever, authors of Women Don't Ask, found that women lose as much as $500,000 over the course of their careers by simply not asking for more from the outset.

It's not that women aren't savvy negotiators—they don't even let themselves enter into negotiations. In my experience, too many women talk themselves out of asking for anything for fear that merely posing the question will somehow count against them. I've seen colleagues shudder at the thought of even requesting a personal day, as though it somehow reflected poorly on their work ethic. The fear is not entirely unfounded: according to a 2006 Harvard study, even when women did negotiate, they incurred discreet penalties for appearing pushy or greedy. Maybe so, but the net effect of passivity—on your income and professional reputation—is far outweighed by the potential upside of asking, be it for a raise, promotion, or more vacation time.

And that's exactly what I explained to my former intern. Think about it: your future boss no doubt invested hours in the hiring process, taking time out of her busy schedule to interview candidates, to justify her decision with colleagues and managers. By the time the offer is extended, she's already invested something in you. She's placed her bets and needs for it to work lest she have to start all over again or recalibrate her thinking on second-best candidates. She really, really doesn't want to do that. It's nearly impossible to imagine a sane, sensible person reacting to a salary negotiation by rescinding the offer. Seriously—think about it. Can you envision her saying, "Three thousand dollars, are you crazy?!" Sounds illogical, right? More likely, she'll say, let me see what I can do (the default answer of many a manager) and get back to you with a yes or a no. That simple. No angry words, no grudges. Just a yes or a no. Turns out that worst case scenario is actually a fairly routine business matter.

So go ahead and ask for that raise. Like my former intern did. She's now $3,000 (pre-tax!) richer for it.

What Do You Think?