In recent weeks, four law firms announced the first-ever, one-year “On Ramp” fellowships designed to help people — primarily women — who left the workforce to start families, care for aging parents or pursue other opportunities get back into the legal profession.

Baker Botts, Cooley, Hogan Lovells and Sidley Austin have chosen nine women out of a pool of 170. The women had been out of the workforce for between three and 20 years. Other “returnship” programs for women who’ve been sidelined have been offered at Goldman Sachs, Sara Lee, Credit Suisse and others. The BBC just ran a piece on the Credit Suisse program.

Some call women leaving the workforce in order to balance work and family life “opting out.” Social scientists who study workplace culture say it’s more like they were “pushed out” because workplaces require long, demanding hours of face time and see flexible or part-time work as almost a sign of weakness. And, unlike in other advanced economies, there are no policies or laws that give real support to working families.

Economist Sylvia Ann Hewlett, of the Center for Talent Innovation, who studies the phenomenon, calls it a “hidden brain drain” that not only hurts women, keeping them down or out of the workforce. It also hurts men by tying them to work even though more, particularly younger men, say what they most want is to spend more time with their children and be equal partners at home. The phenomenon, Hewlett argues,  hurts businesses, families and the economy.

Here’s the Opt Out/Pushed Out story, from Hewlett’s 2004 study of nearly 2,500 highly qualified men and women with advanced degrees, in numbers:

Economists Jane Leber Herr, of Harvard, and Catherine Wolfram, of the University of California, Berkeley’s Haas School of Business, studied the phenomenon among the highly educated using the National Survey of College Graduates and a sample of Harvard alumnae 15 years after graduation. They found that more than 90 percent of those with medical degrees — men, women with no children, and mothers — were working. But for MBA grads, the story was entirely different. About 90 percent of the men and women without children with MBAs were working. But only 71 to 75 percent of the mothers with MBAs were.

Why? The authors say that doctors can set their own flexible hours. And MBAs work in among the most intensive, unforgiving, long-hours cultures around. The authors also found that women who’d worked in flexible and supportive environments before becoming mothers were more likely to return to work afterward. See below:

In another recent study, Joni Hersch, a professor of law and economics at Vanderbilt Law School, found that women who’d attended elite institutions were more likely to leave work after becoming mothers than women who’d attended less selective colleges and universities. The biggest gap? Women with MBAs again. She writes that married mothers with MBAs who’d graduated from elite schools — with enormous tuition bills and years of intensive study — were fully 30 percentage points less likely to be employed full-time than graduates of less selective schools.

Pamela Stone, a professor of sociology at Hunter College, interviewed a number of women for her book, “Opting Out? Why Women Really Quit Careers and Head Home,” and found that not only cultural values of at-home, self-sacrificing motherhood “pulled” mothers home, but inflexible workplaces “pushed” mothers out while keeping their husbands stuck at work. That meant women couldn’t Lean In unless they wanted to outsource all housework and child care, and men couldn’t Lean Out at all.

Over half (60 percent) of the women I spoke to mentioned their husbands as one of the key reasons why they quit. That not all women talked about their husbands’ involvement, or lack thereof, reveals the degree to which they perceived the work-family balancing act to be their responsibility alone. But women seldom mentioned their husbands for another reason: they were, quite literally, absent.

Opt out or pushed out? What do you think? Do you have a story? Share it below, or email me