We all know the economy is bad these days -- have you filled up your car lately? bought milk? checked the stock market? For many families, the one thing standing between them and financial stress is Mom's job. Except that in an economic downturn, women's jobs may be at particular risk, according to a government study released this week.

So don't count on Mom to pay for your gas.

Wives are providing up to thirty percent of household income, the study states, which is a big number, even in a house with two wage earners. In addition, nearly one quarter of kids in this country are being raised by single mothers, which leaves them particularly at risk should Mom lose her job.

Why are women more likely to lose their jobs than men? The study blames this partly on the fact that since the last recession, in 2001, women haven't really found a foothold in the job market again, with fewer women working now than seven years ago. Women are also statistically more likely to lose manufacturing jobs than are their male coworkers. It's possible that this is due to the fact that women, particularly women with kids, often opt for flexible or part-time work schedules, which are typically the first to go in times of economic belt tightening. Or maybe it's just that women are easier to fire.

Anecdotally, I am hearing stories of families who have decided that Mom's job costs too much -- that transportation and day care and other related expenses are outweighing whatever paycheck comes home. Of course, those are moms who are quitting, not getting laid off. Either way, though, it seems that women's jobs are more expendable than men's.