We’re sending our daughters into a workplace designed for our dads.

That’s the headline on a new column that philanthropist and mom Melinda Gates just penned for LinkedIn, where she argues that in “many of the most important ways, our offices are still stuck in the past.” In turn, that’s hurting companies’ bottom lines.

While back in the 1960s, women only made up about 33% of the workforce, today that number is about half. And yet, as the co-chair of the Bill and Melinda Gates foundation points out, the workplace is still set up as if it’s the 1960s when more employees had partners who stayed home caring for the family and tending the house. That means that few U.S. companies today (just 15%) have paid family leave and flexible scheduling. Other family-friendly policies are still hard to come by.

As a result, “many find themselves straining to balance their jobs and their families, and life both at home and at work suffers,” she says. And instead of instituting policies to help workers strained by these responsibilities, “most companies are asking employees to work more,” Gates writes — adding that the average work week has soared from less than 40 hours per week to nearly 50 in roughly the past 60 years.

See also: How much work should you do on a “working vacation”?

In particular, this kind of corporate behavior hurts minority women, Gates writes: “Women, of course, continue to shoulder more of the work at home, meaning many can’t dedicate as much time and energy to their jobs, and some drop out of the workforce entirely. And minorities have less access to networks, mentorship, and resources to help them manage mounting responsibilities at work and at home.”

And that is hurting companies’ bottom lines: “When women and minorities aren’t able to dedicate themselves to advancing their careers, it holds our companies back. Research has proven that teams without diverse perspectives aren’t as innovative or creative. And organizations suffer, too, when employees—both male and female—have to dedicate so much energy to simply keeping their heads above water, instead of thinking of ways to create more value. That slows down economic growth and leads to less prosperity for all.”

She’s right, as an investigation by Fortune shows. And research from 2015 by McKinsey reveals that racially diverse companies outperform the average company by 35% and gender diverse companies by 15%.