In case you’re curious, the only other industrialized countries without paid maternity leave are the Marshall Islands, Micronesia, Nauru, Niue, Palau, Papua New Guinea, Suriname, and Tonga.

This data point — along with a wealth of other numbers about the health, education, and status of women and girls — appears in the “No Ceilings” report recently published by the Clinton and Gates Foundations. It’s a follow-up on 21 years of progress since the 1995 UN Conference on Women held in Beijing.
As the Wharton School of the University of Pennsylvania’s vice dean of executive education, an organizational psychologist, and an executive coach, I wasn’t surprised — unfortunately — by much of the business-related data.

The report highlighted the fact that women’s participation in the U.S. labor force has stagnated (55% of women compared with 82% of men), and that women are still much less likely than men to hold executive management or decision-making roles. This holds true even though women now outnumber men in universities. At Wharton, we have 7,000 to 8,000 executives coming through our courses and programs every year, and the proportion of women to men is nowhere near equitable.

A lack of laws and organizational policies such as paid maternity leave make it impossible for companies to retain women and advance them. Many of today’s female middle managers earned their degrees sitting in classrooms alongside the same or even a lesser number of boys, yet the equality stops there if they happen to want a family. It’s true that there’s more engagement by men with their children these days, and that’s wonderful, but it’s not the same as making a systemic change in organizational policies.

The nuances of advancing a female manager up the ladder are very difficult to navigate. It’s only through powerful, aggressive senior executive advocacy that companies can make the mindset change needed to boost women to that next level of leadership. Many organizations of course have policies and trainings for women, but these are mostly handled by HR departments. And even the best HR person who sits at the table of the business (which itself is rare) will hold little sway over the senior team and the board.

In a conversation related to the report held at NYU between Hillary and Chelsea Clinton and Melinda Gates, Hillary talked about entrenched beliefs: “Even if we get past the laws leveling the playing field… we are left with attitudes.” She commented on how Japanese Prime Minister Shinzo Abe wants to “get our smart, educated women into the workforce” in order to revive his country’s sluggish economy, but is running up against Japan’s cultural biases.

I witnessed similar biases here in the US recently when I sat in on a meeting regarding a high-potential female manager and an upcoming overseas assignment. Because the woman had three young children, her manager decided that the most benevolent, empathetic choice would be to never mention the opportunity to her. But in fact, his decision was paternalistic; it was surrendering to the stereotype. And that’s only one conversation: I guarantee you this will happen tomorrow afternoon to another high-potential female. “Well, she’s got kids, so we’ll give her a chance later.”

I’m heartened, though, by seeing the likes of Hillary Clinton, Chelsea Clinton, and Melinda Gates get behind women’s issues in a high-profile way, and with plenty of hard data. But it’s disappointing that there is no powerhouse leader focused specifically on business. Facebook (FB) COO Sheryl Sandberg tried, with Lean In, and she did manage to reignite the conversation about women’s success in the workplace.

But we need Sheryl Sandberg and someone else. Maybe Nissan’s CEO Carlos Ghosn, who changed his organization in incredible ways and understands the power of transformational change. At the World Economic Forum in Davos this year, he sat on stage talking about women’s leadership. We need someone like him championing the cause of executive women.

And let’s keep the statistics coming. Let’s find out if Google’s (GOOG) reputedly excellent maternity policy actually contributes to its success. Let’s find out which companies increased their market share because of the number of women in senior positions. Then somebody can sit down in this country and say to GE or Procter & Gamble or Colgate-Palmolive, “you need to get on this.” Because, as Hillary put it during the NYU conversation, you’ve got to make more of a case than “you have to treat me the same.” You have to be able to say, “Look at the data and see what you’re losing if you don’t.”

Monica McGrath is the Vice Dean for the Aresty Institute of Executive Education at the Wharton School of the University of Pennsylvania. She is also an Adjunct Assistant Professor of Management focused on women and executive leadership.

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