The scenario most working mothers fear happens when they least expect it.

You've managed to transform your home into a well-oiled machine -- the nanny or sitter arrives in time for you to head out to the office, deal with rush hour traffic, grab a cappuccino and be at your desk milliseconds before your boss walks by your door.

You made it! You beat him or her your desk in your continuing attempts to say:

"I am in complete control of my work and family schedule, thank you very much!"

Then "that" morning arrives.

The nanny is late because of her own personal emergency. And you're faced with a dilemma -- do you 'fess up and tell your boss the real reason you're going to be late or do you lie? Is it better to come up with a story about getting stuck in the world's worst traffic jam or that you overslept rather than explain the real reason for your tardiness?

One recent study says that many women would rather come up with a little white lie about why they're late or have to leave the office early instead of telling the truth if it's because of a childcare snafu, even if they are entitled to take the time away from their desks. Why? Because they believe that in the eyes of their employers, it's better to be seen as someone who accidentally hit the snooze button one time too many times than a mother whose family obligations infringe on the bottom line.

If you're late because the traffic was backed up on I-270 or on the 405, hey -- you couldn't help that! Even the head honcho gets caught in the mother of all back-ups sometimes.

But a surprising number of women fear that their opportunities for promotions or challenging work will be compromised if they let on that they have to have time away from the office occasionally during working hours to tend to their children. Probably because they've seen it happen to others.

Even if employers have "official" flex-time policies, the women polled for this study, that was reported in the U.K's Times Online, reported that bosses and colleagues alike tended to be less understanding if the reason for taking time out of the office was related to childcare or family obligations, and that they worried about what impact that would have on their careers in the long run.

So what do you do?

If your son or daughter has to get picked up at school for a doctor's appointment or the sitter has to leave early, are your honest about your reason for heading out before closing time or do you fudge the truth? And is it time for the government to step in to make sure no parent gets penalized for caring for their family?