We have reached a critical moment in the move to re-evaluate parental leave policies. With today’s release of Anne-Marie Slaughter’s Unfinished Business exploring work-life balance, the recent letter to Congress from 203 US business school professors in support of the new Family And Medical Insurance Leave (FAMILY) Act, and the tech industry’s race to expand parental leave, there’s a national spotlight on what companies are doing to ensure paid time off for new parents.

Silicon Valley, already known for generous leave policies, has seen a surge in parental leave recently. In early August, Netflix announced big news for new parents at the company: employees with a new child (through birth or adoption) will be allowed to take up to a year of paid time off. A day later, Microsoft, and soon after, Adobe, quickly followed suit, expanding parental leave policies in rapid succession and potentially marking a new era for working parents in the tech world.

Starting November 1, Microsoft’s policy grants new parents 12 weeks off and birth mothers 8 additional weeks of disability. On the same date, Adobe Systems will offer 16 weeks for parents plus 10 more weeks for new birth mothers. These policies put these companies in the same league as Google (offering 18 weeks to birth moms) and Facebook (offering 16 weeks to new parents), making them increasingly more attractive workplaces for new and prospective parents.

There are several motivations here. It’s no secret that the tech world is taking steps to address its gender inequality problem, making strides to recruit more women and close the gender gap. Intel recently announced its intention to reach full representation of women and minorities by 2020. And these companies hope that the new parental leave policies will help them come across as more appealing places for women to work. With generous parental leave policies for both parents, women have less to fear about being edged out at work or passed over by a male colleague–or about not being hired in the first place–the so-called “motherhood penalty.”

But it’s not just for the women; Netflix, Microsoft, and Adobe want to attract and retain the best employees, of either sex, by being viewed as compassionate environments that support a healthy work-life balance for employees. There’s a financial incentive, too. “It’s very expensive for companies to replace workers who chose to leave because you don’t have generous policies,” said Anne Marie Squeo, Netflix’s spokesperson.

Matt Brosseau, CTO and IT staffing and recruiting with the firm Instant Alliance, agrees: “It costs roughly 6-9 months of the employee’s salary to replace them if they leave. That cost is huge.”

By US standards, these new leave policies are generous. Under the Family and Medical Leave Act, employers are required to offer 12 weeks of leave to new mothers–but that’s unpaid leave, and that’s only for companies employing more than 50 workers. The US is one of four countries in the world that does not offer a federally guaranteed paid leave, and the only developed country in the world not to require it. Even these newly expanded leave policies don’t come close to standard practices in Europe. Sweden, for example, offers all employees 16 months of paid parental leave. And Cuba offers 18 weeks of paid maternity leave. Still, it’s important to note that Netflix, Microsoft and Adobe–as well as the tech industry in general–are offering far more liberal policies than is typical in this country.

But how will these changes really affect workers? The announcements have their skeptics. Some worry that the plans are not inclusive enough. Netflix’s policy, for example, only applies to “talent” or salaried streaming employees, leaving out more than 400 lower-level workers who make up a significant part of their 2000+ employee base.

Another major concern is that these workplace cultures won’t adequately support the policies they’re offering. A recent expose of Amazon’s harsh workplace environment–one in which it wasn’t uncommon to find employees crying at their desks–portrayed Amazon as a workplace where employees felt pressure to forgo vacation and parental leave time in order to keep their jobs. This shows the dangers of the “punishing aspects of the workplace” and a culture that doesn’t support leave. It should be noted that Amazon’s parental leave policy, disclosed following the article, grants new mothers eight weeks of paid and 12 weeks of unpaid leave. No leave is granted to new fathers. This policy leaves the company far behind its peers in the tech industry.

While the portrayal may be extreme–“Amazon stands alone in its particular culture,” Brosseau tells me–it is true that open-ended time-off policies are not guaranteed to be effective. Many employees who are granted these benefits do not feel comfortable taking them if they want to continue to be seen as hard-workers. A recent Labor Department Survey shows that 70% of men took only 10 days of paid time off after becoming new fathers, stating that “there may be a cultural stigma around taking significant leave in certain industries.” Unless the culture of the company supports and enforces parental leave policies with concrete guidelines, employees may worry about being edged out of their jobs.

“The most important factor, said Stephanie Coontz, historian and Director of Public Education at the Council on Contemporary Families, “is not the policy itself but the attitude of immediate supervisors. It depends how supportive they are, and how much the workplace culture encourages leave-taking as a norm, not a special privilege.”

Jay Garmon, former TechRepublic staff member and tech startup entrepreneur, agreed. Garmon has worked in companies with both explicit and open-ended leave policies. When he worked for another publisher, TechTarget, that had an open-leave policy, he could take off at any point. But it didn’t happen. “Your worth was implicitly measured by how little time off you took,” Garmon said. ZirMed, the company he currently works for, has an explicit leave policy. If he doesn’t take time off, Garmon said, “the manager will come and say ‘You’re taking off sometime in the next pay period.'” Ultimately, for leave policies to work, “it needs to be ingrained in the culture that it is an expectation that you will take leave,” Garmon said.

Squeo stresses that Netflix’s leaders “thought about the policy through the prism of the culture.” Their open-ended policy, she said, fits the company’s emphasis on “freedom and responsibility.” And Netflix’s guidelines are unique to that company, Squeo said–not a “one-size fits all.”

The biggest change, Squeo said, came in 2004 when Netflix decided to offer unlimited vacation time–a move drawing similar criticism about how realistic it is that workers will take it. She’s personally used it to take Fridays off this summer, Squeo said, but employees can “interpret the policy however it works for them.”

When asked about how the vacation policy has actually affected the company, however, Squeo can’t answer: since Netflix allows limitless time off, she said, there’s simply “no way to track it.”

Tracking time off may be part of a larger issue–that Americans simply are on the clock longer hours. Brosseau explains: “The 9-5 is long-since past. Everyone is online, all the time. Unlimited vacation allows people to take the time they need–but they’re probably still online.”

The parental leave policy, Brosseau said, is different from unlimited vacation. “It sends a direct message,” he said. “It shows there’s a deeper emphasis on family. That these tech companies are growing up, just like their staff are.”

While these policies do not cover employees at all levels, and while we have yet to see how they are actually used, it’s hard not to see them as a gain. The most important thing, according to Coontz, is for us to see leave-taking as a norm.

“This is the next frontier in gaining equality for women in the workplace and equality for men in family life,” she said.