Krawcheck identifies a number of traits that unite these “third act” career moves—including a strong focus on giving back. That’s an appropriate theme to introduce Fortune’s May 4th “Most Powerful Women Evening With…” dinner in Washington, D.C.—the kick-off event for the Fortune/U.S. State Department Global Women’s Mentoring Partnership.

This public-private program brings women from emerging markets to the U.S. to be hosted by senior female executives. It wouldn’t be possible without women who, as Krawcheck describes, have reached some of the highest ranks in their respective industries and are willing to devote time and energy to making a difference in the world.

Here’s what working mothers are told again and again: The early years of your kids’ lives are going to be tough. Suffering from sleep deprivation while trying to establish your career and get your kids off to a good start in life is no piece of cake. I remember feeling like I was holding onto my career by my fingertips, operating through a fog of exhaustion, barely able to stay awake in the mid-afternoon hours. And the pictures of me from those days—all I can say is, “Wow.” There wasn’t enough under eye cover-up on Earth.

Then come the teenage years, which—surprise!—can be even tougher. While you’re likely more established in your career, teens also demand your attention, and often in a more nuanced way than they did when they were young. Less “I have a boo-boo” and more “My friends are smoking pot; how do I handle this?” It’s unpredictable and time consuming. Plus, for me at least, sleep deprivation was back in full force. (My daughter never met a curfew that she didn’t cut too close.)

But then they head off to college.

Now, here’s the working mom secret they don’t tell you: This empty-nest moment can be a career renaissance for women. Yes, I miss my kids; I miss them like crazy. But suddenly I have oceans of time, not to mention the ability to sleep through the night without interruption. My energy level is through the roof. I have decades of career experience behind me—and at least a couple of decades of work that still lie ahead.

Sign up: Click here to subscribe to the Broadsheet, Fortune’s daily newsletter on the world’s most powerful women.

It’s not just me. A number of my female peers are recommitting to their careers at this stage of their lives. It has the feel of a new beginning, with many reporting a sense of enjoyment of work that was hard to come by when were doing the work-kid balancing act. In contrast, when I’ve asked my male peers whether they’re experiencing a similar renewal, they just look at me quizzically. Maybe that’s because women continue to do the majority of the child-related heavy lifting in many households—I’ll admit it, mine is one: I shouldered the curfew worries while my husband slept soundly through it all.

While some women use this period to double down on their current career, others seize it to try something new, something entrepreneurial. According to the Kaufmann Foundation, people ages 55 to 64 made up 26% of new entrepreneurs in the US in 2014, up from 15% in 1996.

Part of this entrepreneurial push comes from the fact that women in this stage of their lives are more financially secure and therefore open to taking on more career risk. At the same time, the cost of starting businesses is declining substantially. Think cloud computing instead of buying servers, WeWork instead of long-term leases, video chat instead of business trips and, in some cases, freelancers instead of full-time employees. These shifts have made entrepreneurialism more accessible than ever before, opening it up to people who wouldn’t have considered it as a viable option even a handful of years ago.

Another trend I see among these new businesses: Many are underpinned by a real sense of mission, and a commitment to making a difference. Again and again, I hear, “If I’m going to throw myself back in, I want to throw myself back in to something that can matter.” Just a few examples that spring to mind:

Susan Lyne is now running BBG Ventures (for Built by Girls), a venture capital fund sponsored by AOL that funds women-led businesses, after a career at companies such as ABC Entertainment and Gilt.

Deborah Jackson transitioned from her years at Goldman Sachs to found Plum Alley, a crowdfunding site for women entrepreneurs.

After making a name for herself at JP Morgan, Blythe Masters is leading and building Digital Asset Holdings, a blockchain startup that has the potential to transform her former industry.

Jacki Zehner left a career as the youngest female partner from the trading businesses at Goldman Sachs and is now the chief engagement officer of Women Moving Millions, a nonprofit devoted to investing in women and girls.

I’ve done it too, starting Ellevest, a digital investment platform for women. I know that for me, the mission—rethinking the investing process in order to better serve women, hopefully closing the gender investing gap—was paramount.

There is one more factor that may be facilitating this shift. As I watch my peers navigate this stage, it occurs to me that our culture allows women to learn, to explore, to be uncertain in a way that men cannot. For once, a gender stereotype that goes our way! Because our society doesn’t box us into the archetype of manly decisiveness and certainty we are allowed to learn and experiment throughout our lives.

These late career reinventions mean women will work—happily—for longer, creating a bigger economy, saving more for retirement and providing more talent for companies to draw upon.

So are we entering a world in which women’s careers peak later than men’s? In which the guys continue to build straight-line careers—where one step leads to the next—while women take a more scenic route, blending career and childcare in their children’s younger years, then roaring back in their third acts?

I’m not saying this will be the case for everyone, but the model is certainly working for some. Just ask Bill and Hillary.

Sallie Krawcheck is the CEO and Co-Founder of Ellevest, a digital investment platform for women, to be launched in 2016. You can sign up for early access here. She is a Wall Street refugee, having run Merrill Lynch Wealth Management and Smith Barney. She has been named one of Fast Company’s most creative people in business.