Katerina loves her job managing special projects for a major west coast museum. She's constantly exposed to new artists, and takes regular business trips to Asia. Best of all, she works with a group of nearly all women who are genuinely interested in and enlivened by creativity. But last fall, when her coworker Ruth got pregnant, Katerina was surprised at how much resentment the situation stirred up. While Ruth was on maternity leave, Katerina inherited most of the extra work with no increase in salary. When Ruth came back, she shifted to a four-day week and left every evening by five while Katerina remained at the office an hour later, still struggling to pick up the slack.

"I felt so guilty," she admits. "I can't imagine how tough it must be to work and have a baby. I really wanted to support Ruth. But to be honest, I was also angry. I felt like she was taking advantage of me."

Several weeks after hearing from Katerina, I met Leslie, a corporate PR executive with two children under six, who was overflowing with stories about how little her female boss--the mother of two teenage sons--was willing to help Leslie manage work-family issues.

"She schedules late meetings, no matter how often I tell her I need to leave by six," Leslie explained. "I'm supposed to be off every other Friday but inevitably some crisis comes up and I spend all day at home dealing with work. I don't understand how she can be so hard-nosed, when she knows exactly what it's like to work and raise kids at the same time."

Like Leslie, many of us expect our female colleagues to be more supportive on the work-family front than their male counterparts, especially if they've had kids themselves. We assume they'll understand when we have to schedule an emergency doctor's visit or work from home two days a week. And it can feel like the worst sort of betrayal when they let us down. Like Katerina, we also feel incredibly guilty when we don't naturally overflow with that same brand of selfless support ourselves.

The media has jumped on the so-called war between working and stay-at-home mothers. But what about the very real conflicts that can rise up among mothers and non-mothers on the job?

Professional women today are under incredible pressure to do it all. We're expected to manage wildly successful careers, raise perfect children on homemade organic baby food and hand-sewn Halloween costumes, keep the marriage exciting, and stay slim and ravishing to boot. It's impossible. Something has to slide, and usually it feels like everything is sliding at once. We need support from our female colleagues, and we like to think they need our support too. So how are we supposed to react when they can't or won't come through in a work-family pinch?

Step one is the simplest. Don't judge. Most women harbor insecurities over whether they've made the right life choices. We look to each other for cues as to how well we're managing things. But our personal lives these days take on all kinds of shapes. Especially when we're feeling uncertain about our own choices, it can be tough to accept that another woman's very different set-up may be just as "right" and valid as our own. Married or single, children or childless, full-time or part-time, every option is equally legitimate. The trick is finding one that works best for you.

Next, when your female coworker seems unwilling to extend her support, look closely at where she's coming from. Even your boss may not have as much autonomy within the company as you think. Is it really within her power to rearrange meetings with clients to accommodate your schedule? Or would taking such a step put her job at risk too? Often, the individual problems we encounter are rooted in company-wide flaws. Instead of beating herself up about being angry with Ruth, Katerina might have been better served to look into potential changes in how the museum handled the work distribution for maternity leave and part-time employees.

If the situation really does feel unfair, don't just sit there and let the resentment build. Say something. Call a meeting with your boss or coworker. See if there's a way you and your flextime colleague can more fairly share the workload. Armed with stats and spreadsheets, talk to your boss about how to rearrange your week so you can spend time with your kids. Be proactive about getting the sort of schedule and support you need.

Above all, be as generous as you can possibly be. Too often, official company policies don't cover all of our work-family needs, meaning we depend on personal relationships with our colleagues -- especially other women --to pull us through. Sometimes, being supportive will require a selfless act or two on your part. Stay late. Rearrange a meeting. Give a stressed out employee the afternoon off. Think of it as generating some good office karma. And who can't use that somewhere down the line?