I know quite a few couples where the woman gave up her career after the first kids arrived. In most of these cases, the woman was better educated than her husband and had better grades and prospects of earnings. Still, the women gave up work and stayed home. A pity for the economy, I thought at the time. The families, as well as the country would have been richer, had these women worked. Some returned to work when the children entered school, but their career path was disrupted once and for all.
I always assumed their choice to stay home was voluntary. But recently another fact about them struck me: with the exception of one couple, they all live in the countryside. And the one wife that lives in the city was actually the first to return to work.
Dora Costa and Matthew Kahn digged up more data on this and found that dual career couples tend to choose to live in cities. A metropolitan area holds the key for more job prospects for both partners.