http://economix.blogs.nytimes.com/2013/01/04/womens-unemploy...
A society which views it as more acceptable for women to opt-out of the labor force may distort this: when employment becomes less scarce, women may be more likely to opt-out of the labor force -- since unemployment measures (actively looking for work) / (employed + actively looking for work), people dropping out of the active labor force when out of work shows up as lower unemployment, but it doesn't mean "more options" for those in the labor force.
We've been in that situation for 5 years in the US. What you're describing did not happen—declines in labor participation among men still exceed women by a significant amount.
One explanation I've heard is that since women earn less, but do "the same" work, it's cheaper to keep them on vs. men. I have no idea if that's correct or not, or if it is, explains the difference.