Most men aspire to be egalitarian. They really do.

It’s just that life — by which I mean employers, social pressures and tax policy — gets in the way.

Harvard Business School recently released some heavily dissected survey data on the career paths of 25,000 alumni. The findings that got the most attention related to women’s initial expectations — ultimately dashed — of achieving family arrangements that would allow their own careers to flourish. But the most interesting results, in my opinion, related to the men surveyed.

While Harvard women said they had (often wrongly) expected to land in egalitarian partnerships, Harvard men said they’d known all along that they would end up in relatively traditional, 1950s-style nuclear families. Majorities of men said that, at the time of graduation, they expected that their own career would take precedence over their spouse’s and that their spouse would take primary responsibility for the kids.

So what’s going on here? Are Crimson men just sexist jerks?

They certainly look more chauvinistic than American men more broadly. At least at first blush.

In 2011, CBS News polled Americans on which kind of marriage offered the more “satisfying way of life”: one where the man works and the woman takes care of house and children, or one where both spouses have jobs, do housework and take care of the kids. Perhaps unsurprisingly, men were more likely than women to say they preferred the more traditional arrangement. Here’s what was surprising: Even among the men, the marital traditionalists were a small minority. That is, two-thirds of men professed a preference for egalitarian marriage.

In fact, at every income level and age group (even the “Mad Men”-era types!), a majority of men said they preferred marriages in which both partners worked and shared household and child-care responsibilities.

This is perplexing. In reality, such marital arrangements are not the norm. Women are far more likely to be the primary caregivers and to be out of the labor force than men are when in two-parent households (which are on the decline, by the way). Somehow these egalitarian aspirations are not materializing.

Economists often distinguish between “stated preferences” and “revealed preferences.” (You might say you love salads, but if you’re ordering burgers every meal, you’ve revealed a different preference.) Maybe survey respondents are just trying to sound enlightened. I’m inclined to think their answers are genuine, though; their ideals are just not compatible with the institutions and social norms around them.

“Truly egalitarian fathers have to make sacrifices at work,” says Kathleen Gerson, a New York University sociology professor and author of “The Unfinished Revolution.” “That’s something they’re not always prepared to do.”

After decades of rhetoric validating women’s choices to “opt in” or “opt out,” women often resolve work-life conflict by pulling back from work. That’s less often true for men, who are still plagued by a masculine mystique that says they need to be strong breadwinners. Bosses and co-workers frown upon men who request flexible schedules or parental leaves, too. Perhaps as a result, survey data show that fathers today report greater levels of work-life tension, along with anguish about not being home enough, than mothers do. Men usually earn more than their wives, too, which makes it especially financially painful for them to ratchet back at the office. (This calculus amplifies the gender pay gap, of course.)

Whatever their preferences for a “satisfying” marriage, spouses deal with the constraints they face by reverting to traditional, specialized and frequently unsatisfying gender roles.

Which brings me back to the Harvard results. I suspect the real reason these elite men seek out traditional male-breadwinner families is not that they believe the Second Sex deserves to stay barefoot, house-coated and pregnant. It’s that they’re practical. They spent two years studying how to develop successful careers and businesses, which includes understanding both how real-world companies work and what kind of team (at work, and at home) one needs to thrive financially.

They’re also members of a socioeconomic class that invests substantially more time in their children today than in the past, meaning they may feel they need a spouse who has time to be an active parent. Sure, Harvard MBAs may have greater resources to hire help so both spouses can work in demanding careers, but the tax system, through both the marriage penalty and nanny taxes, often discourages them from doing so.

Such institutional obstacles to equality can reinforce normative ones, of course (like that masculine mystique I mentioned earlier). But our norms are already evolving. It’s the institutions that are standing in the way of real progress.