This was some two decades before a tidal wave of wives and mothers went into paid work.
For the relatively few women with four-year college degrees, this change was the consequence of wider educational opportunity and new laws against gender discrimination that opened professions to well-educated women.
But the vast majority of women entered the paid workforce because male wages were dropping. Globalization and automation were pushing men out of well-paid factory jobs. Unions were crumbling. Wives and mothers had to get paid jobs in order to prop up family incomes.
The change was drastic. In 1966, only 20 percent of mothers with children worked outside the home. By the late 1990s, it was 60 percent.
For married women with children under age 6, the transformation was even more profound: from 12 percent in the 1960s to 55 percent by the late 1990s.
It was one of the largest transformations of the American family in history. Yet America still hasn't accommodated this shift.
I was proud to have implemented the Family and Medical Leave Act when I was labor secretary. But unlike most rich nations, America doesn't require that employers offer paid leave. As a result, women and many families can't afford to leave work for a newborn baby or a medical emergency.
Nor does America require equal pay for equal work. Women's pay still lags behind male pay for the same job. This is true even for college graduates.
Nor, like most rich nations, do we provide universal child care. Instead, families are offered a patchwork of small subsidies, tax deductions and tax credits that fail to meet most families' needs. And even the modest child-care subsidies have fallen under the budget ax.
More women workers are in minimum-wage jobs than men, yet the minimum wage hasn't kept up. If it had stayed even with inflation since 1968, it would be over $10 today.
We've even cut aid for prenatal and postnatal medical care for poor infants and mothers.
And we have put a five-year limit on aid to single women with children -- a limit that the ongoing effects of the Great Recession have already proven onerous.
Nor, finally, have we begun to cope with the reality of stagnant or declining real wages that has caused families to work so much harder and longer in the first place.
Globalization and automation continue to erode the wages of most Americans. The typical male worker today is earning less, adjusted for inflation, than he did three decades ago.
Most of the new jobs created since the recession bottomed out in 2009 pay less than the jobs lost in the recession. The fastest-growing jobs are in retail shops, restaurants, hospitals and hotels -- whose pay and benefits are low.
But this doesn't have to be the case. Other rich nations, such as Germany, have invested heavily in technical education and job training, so their workers use new technologies to become more globally competitive.
Here, though, we've slowed investments in our people -- making it harder for young people to get the skills they need. Public higher education has become unaffordable to many.
In America, almost all of the economic gains since the late 1970s have gone to the top 1 percent.
Too many of our representatives in Washington refuse to acknowledge any of this, or take the necessary steps to reverse the trend.
They profess to believe in "family values." But their indifference and inaction in the face of what has happened to working families poses a clear and present danger to the American family.
Robert Reich, former U.S. secretary of labor, is professor of public policy at the University of California at Berkeley and the author of "Beyond Outrage," now available in paperback. He blogs at www.robertreich.org.