NEW YORK (CNN/Money) - To work or not to work. That is the question that nearly every parent struggles with at one time or another, whether it's when little Suzie says her first words or goes to her first Britney Spears concert.

In today's career-driven society, it's occasionally the fathers who must decide, particularly those who earn less than their wives. Statistically, however, it's still moms who are far more likely to put their own careers on hold.

The Census Bureau reports that fathers continue collecting a paycheck in 90 percent of single-income married households.

That's not to say, however, that all mother's stay home with the kids. Indeed, the majority of women with children these days work outside of the home, whether out of choice or necessity. According to 2000 Census data, 64 percent of all families with children under 18 are two-income households. Among families with incomes above $75,000, that proportion rises to 76 percent.

Yet, when you consider the cost of childcare, lost tax breaks, and the extra expenses associated with going to work, staying in the work force may actually cost more than staying at home -- at least in the short term.

If dropping the kids off at daycare each morning doesn't break your heart, it certainly breaks the bank. Unless Grandma and Grandpa live nearby and are eager to look after your children for free, your largest expense associated with full-time employment will likely be childcare.

According to the Children's Defense Fund, the annual cost of sending an infant to childcare in urban areas ranges from $3,900 in Conway/Springdale, Ark. to $12,978 in Boston -- per child. Although these numbers do come down as your children get older, they are still staggering. In fact, the average cost of infant childcare in urban areas outweighs the average cost of college tuition at public schools. In some cities, it's twice as much. And if you hope to have a nanny look after your children in your home you can expect to pay the equivalent of one year of college tuition at a private school.

To see the average price of childcare in rural and urban areas in each state, download the Children's Defense Fund's 2000 report on childcare costs and read the tables toward the back of the report.

The good news is, some childcare costs are offset by tax benefits. Many companies allow you to save as much as $5,000 a year for childcare, pre-tax, in a flexible spending account. If you and your spouse gross $140,000 a year, this $5,000 contribution could save you more than $1,800 in state and federal income taxes. Depending on how much you make and whether you take advantage of flexible spending benefits, you may also be able to claim childcare credits for up to $2,400 in expenses per child.

After childcare, there are a number of other expenses attached to working outside of the home, including but not limited to transportation costs, professional attire, dry cleaning and meals eaten out.

"You realize that it's the little costs that break you," said Mary Snyder, who quit her job as a marketing manager for a Fortune 500 company in 1996 and co-wrote the book "You Can Afford to Stay Home with Your Kids" in 1999. In fact, she estimates she was spending more than $900 a month on work-related expenses, not including childcare and after-school programs.

To understand what you'll save by staying home, try keeping a detailed diary of all work-related expenses for several months. Be sure to factor in commuting costs, lunches out, dry cleaning and any business clothes you need to buy. Keep track, too, of any extra dollars you drop because free time is limited: convenience foods for dinner, ATM fees, and lawn care or housekeeping services.

Once you have a good idea of what you spend to go to the office, come up with a realistic estimate for what you'll spend staying home. Consider the difference between the two as your true work-related expenses.

Just remember that you'll still need to eat while you're home, even if it's just leftover macaroni and cheese and an occasional lunch with grownups. Also, by staying home you may spend more on other things, such as long-distance phone calls, a new hobby, and the occasional babysitter.

Snyder said she believes that parents who make less than $50,000 a year should look carefully at how much they're really bringing home.

When weighing the benefits of one income versus two, it's also important to consider the tax implications. With one income you might not only be taxed at a lower bracket, you might also qualify for deductions and exemptions that phase out when both of you are working. Therefore the difference between what you take home with just one salary and two salaries may not be as much as you think.

For example, a couple living in the state of New York with a combined income of $140,000 could save more than $21,000 in federal and state income taxes if they live on a single income of $80,000, says Alan Langer, tax director of the Deloitte & Touche private client advisor group, adding that this figure does not include what they'd save on Social Security. On top of that, they'll be eligible for up to $600 in child credits per child if their combined income is less than $110,000. (The credits gradually increase to $1,000 in 2010.) In other words, by going from two incomes to one, this couple would lose 42 percent of their income before taxes, but only 36 percent of their income after they consider the lower tax bracket and $1,200 in child credits.

Before you bid farewell to the boss, however, there are a few more numbers to consider.

When you quit working, you don't just lose your biweekly paycheck, you also lose health benefits (not an issue if your working spouse has good benefits), retirement savings, the free life and disability insurance your company might offer and a laundry list of other perks.

The loss of retirement savings alone could be particularly painful. For example, if you make $60,000 a year and save 10 percent of your pretax income in your 401(k), you'll be able to save $6,000 a year tax-free. Add to that your company's matching benefits, which is typically 50 cents on the dollar, and you would be saving $9,000 a year. That's three times the $3,000 maximum contribution for Individual Retirement Accounts.

Moreover, by taking yourself out of the work force for a few years, you could be reducing your lifetime earnings potential by quite a bit. "That time away from the workforce turns out to be a huge cost in terms of advancement and promotions, and women never catch up," said Sharman Stein, articles editor for Working Mother magazine. "This is one of the reasons why pay equity between men and women is lagging."

Of course, numbers tell just part of the story. Some parents decide to stay home or keep working regardless of the financial implications. Often, parents who are fully prepared to go back to work change their minds the second their babies are born. Or they realize shortly after they quit their jobs that they can't wait to get back to the office.

As such, it's important to plan for either scenario.

Stein recommends you start by researching your company's maternity and work/life policies even before you start a family, if possible.

The good news is that more companies are recognizing the need for balance between work and home, offering family-friendly benefits even in today's tough job market. "In 2002 we have a much more flexible workplace than we've ever had before," said Stein, noting that companies continue to offer such things as flexible hours, job sharing, telecommuting, extended maternity leaves and childcare. "Every year we see companies doing more and more to help parents accommodate the demands of work and home."

If your company doesn't already have such programs in place, ask anyway. "Any woman should feel comfortable proposing a new job arrangement," said Stein. If you don't think your employer will budge on its policies, start sending your resume to companies that will.

At the same time you research more flexible career opportunities, take steps to make staying at home a reasonable option.

Elizabeth Lewin, co-author of "Family Finance," said it's wise to live on one income before you start a family: "Put that second salary away while you're doing this."

If you manage to save your second income throughout the pregnancy, you'll not only ease some of the anxiety that comes with the idea of living on one paycheck, you should be able to pay off some of your debt (thereby reducing your monthly expenses) and start a nice big diaper fund as well.