Today in the United States and the developed world, women are better off than ever before. But the blunt truth is that men still run the world. While women continue to outpace men in educational achievement, we have ceased making real progress at the top of any industry. Women hold around 14% of Fortune 500 executive-officer positions and about 17% of board seats, numbers that have barely budged over the last decade. This means that when it comes to making the decisions that most affect our world, our voices are not heard equally.

It is time for us to face the fact that our revolution has stalled. A truly equal world would be one where women ran half of our countries and companies and men ran half of our homes. The laws of economics and many studies of diversity tell us that if we tapped the entire pool of human resources and talent, our performance would improve.

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Throughout my career, I was told over and over about inequalities in the workplace and how hard it would be to have a career and a family. I rarely, however, heard anything about the ways I was holding myself back. From the moment they are born, boys and girls are treated differently. Women internalize the negative messages we get throughout our lives—the messages that say it’s wrong to be outspoken, aggressive, more powerful than men—and pull back when we should lean in.

We must not ignore the real obstacles women face in the professional world, from sexism and discrimination to a lack of flexibility, access to child care and parental leave. But women can dismantle the internal barriers holding us back today. Here are three examples of how women can lean in.

Don’t Leave Before You Leave

A few years ago, a young woman at facebook began asking me lots of questions about how I balance work and family. I inquired if she and her partner were considering having a child. She replied that she did not have a husband, then added with a little laugh, “Actually, I don’t even have a boyfriend.”

From an early age, girls get the message that they will likely have to choose between succeeding at work and being a good wife and mother. By the time they are in college, women are already thinking about the trade-offs. In a survey of Princeton’s class of 2006, 62% of women said they anticipated work/family conflict, compared with 33% of men—and of the men who expected a conflict, 46% expected that their wives would step away from their career track. These expectations yield predictable results: among professional women who take time off for family, only 40% return to work full time.

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But women rarely make one big decision to leave the workforce. Instead, they make a lot of small decisions along the way. A law associate might decide not to shoot for partner because someday she hopes to have a family. A sales rep might take a smaller territory or not apply for a management role. A teacher might pass on leading curriculum development for her school. Often without even realizing it, women stop reaching for new opportunities. By the time a baby actually arrives, a woman is likely to be in a drastically different place than she would have been had she not leaned back. Before, she was a top performer on par with her peers in responsibility, opportunity and pay. But by not finding ways to stretch herself in the years leading up to motherhood, she has fallen behind. When she returns to the workplace after her child is born, she is likely to feel less fulfilled, underutilized or unappreciated. At this point, she probably scales her ambitions back even further since she no longer believes that she can get to the top.

There are many powerful reasons to exit the workforce. No one should pass judgment on these highly personal decisions. My point is that the time for a woman to scale back is when a break is needed or a child arrives—not before, and certainly not years in advance. For those who even have a choice, choosing to leave a child in someone else’s care and return to work is a hard decision. Anyone who has made this decision—myself included—knows how heartwrenching this can be. Only a compelling, challenging and rewarding job will begin to make that choice a fair contest.

Success and Likability

In 2003, Columbia Business School professor Frank Flynn and New York University professor Cameron Anderson ran an experiment. They started with a Harvard Business School case study about a real-life entrepreneur named Heidi Roizen. It described how Roizen became a successful venture capitalist by using her “outgoing personality … and vast personal and professional network … [which] included many of the most powerful business leaders in the technology sector.” Half the students in the experiment were assigned to read Heidi’s story. The other half got the same story with just one difference—the name was changed from Heidi to Howard.

When students were polled, they rated Heidi and Howard as equally competent. But Howard came across as a more appealing colleague. Heidi was seen as selfish and not “the type of person you would want to hire or work for.” This experiment supports what research has already clearly shown: success and likability are positively correlated for men and negatively correlated for women. When a man is successful, he is liked by both men and women. When a woman is successful, people of both genders like her less.

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I believe this bias is at the very core of why women are held back. It is also at the very core of why women hold themselves back. When a woman excels at her job, both men and women will comment that she is accomplishing a lot but is “not as well liked by her peers.” She is probably also “too aggressive,” “not a team player,” “a bit political”; she “can’t be trusted” or is “difficult.” Those are all things that have been said about me and almost every senior woman I know.

The solution is making sure everyone is aware of the penalty women pay for success. Recently at Facebook, a manager received feedback that a woman who reported to him was “too aggressive.” Before including this in her review, he decided to dig deeper. He went back to the people who gave the feedback and asked what aggressive actions she had taken. After they answered, he asked point-blank, “If a man had done those same things, would you have considered him too aggressive?” They each said no. By showing both men and women how female colleagues are held to different standards, we can start changing attitudes today.

Stop Trying to Have It All

having it all. perhaps the greatest trap ever set for women was the coining of this phrase. No matter what any of us has—and how grateful we are for what we have—no one has it all. Nor can they. The very concept of having it all flies in the face of the basic laws of economics and common sense. Being a working parent means making adjustments, compromises and sacrifices every day.

For most people, sacrifices and hardships are not a choice but a necessity—and tougher than ever because of the expansion of working hours. In 2009, married middle-income parents worked about 81⁄2 hours more per week than in 1979. Just as expectations about work hours have risen dramatically, so have expectations of how much time mothers will spend focused on their children. An employed mom today spends about the same amount of time reading to, feeding and playing with her children as a nonemployed mother did in 1975.

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One of my favorite posters on the walls at Facebook declares in big red letters, done is better than perfect. I have tried to embrace this motto and let go of unattainable standards. My first six months at Facebook were really hard. A lot of my colleagues followed Mark Zuckerberg’s lead and worked night-owl engineering hours. I worried that leaving too early would make me stand out like a sore—and old—thumb. I missed dinner after dinner with my kids. I realized that if I didn’t take control of the situation, my new job would prove unsustainable. I started forcing myself to leave the office at 5:30. Every competitive, type-A fiber of my being was screaming at me to stay, but unless I had a critical meeting, I walked out that door. And once I did it, I learned that I could.

I do not have the answers on how to make the right choices for myself, much less for anyone else. I do know that I can too easily spend time focusing on what I am not doing. When I remember that no one can do it all and identify my real priorities at home and at work, I feel better—and I am more productive in the office and probably a better mother as well. Instead of perfect, we should aim for sustainable and fulfilling.

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I believe that if more women lean in, we can change the power structure of our world and expand opportunities. Shared experience forms the basis of empathy and, in turn, can spark the institutional changes we need. More female leadership will lead to fairer treatment for all women. We also need men to lean into their families more, especially since research has consistently found that children with involved and loving fathers have higher levels of psychological well-being and better cognitive abilities.

The hard work of generations before us means that equality is within our reach. We can close the leadership gap now. Each individual’s success can make success a little easier for the next. We can do this—for ourselves, for one another, for our daughters and for our sons. If we push hard now, this next wave can be the last wave. In the future there will be no female leaders. There will just be leaders.

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