Now that Hillary Clinton has locked up the Democratic nomination for president, she is one step closer to breaking the “highest, hardest glass ceiling” in American politics. If she wins, would her presidency bring more women into political office in the United States?

That’s very possible — even probable. At least, that’s what we can conclude from my new paper about the 50 countries where, since the 1950s, women have held the highest office, such as president or prime minister.

On average, when a woman becomes a country’s chief executive, that country starts electing more women to the legislature

The graph below shows that the number of countries with a woman holding its highest office has generally been increasing since 1960. In the spring of 2014, 18 countries had a female leader. Although the figure has dropped recently, women are now leading as many countries today as they did at any point before 2009. Some female leaders, like Clinton, come from powerful political dynasties. But without exception, each of the women currently serving in her country’s highest office was elected in her own right and did not inherit the position from her father or her husband.

But of these 50 countries, only 12 — including Norway, Bangladesh and the Philippines — have had a second woman as the country’s top leader.

In other words, electing a female leader doesn’t vastly increase the likelihood that it will happen again. But electing a female leader does appear to boost the number of women those nations elect to their legislatures. Let’s look at the data.

Once a nation has a female leader, it elects more women to its legislature 

According to the World Bank’s Gender Data Portal, women make up an average of 20.6 percent of democratically elected parliaments, assemblies and congresses. In countries where a woman has never been in power, that number is 18.6 percent — but in nations where a woman has held the highest office, the number is 24.1 percent.

We know that correlation doesn’t equal causation. There could be other reasons these legislatures have more women. For instance, the kind of countries that elect a woman to the top office might also have gender quotas for political lists, greater economic opportunities for women, or a more progressive political culture that encourages people to see women and men as equals. To check, I did a statistical analysis that models women’s representation while accounting for those and other factors across more than 100 democracies from 1997 to 2014. And what I found was that — all other things being equal — yes, electing a female leader appears to result in that country electing more women to the legislature.

Once democracies have had a female leader, they have on average about 4 percent more women in their legislatures than those that have not. And 4 percent is a lot. In most countries, that’s dozens of legislators, enough to potentially influence what legislation gets passed.

That boost in female representation in legislatures persists for at least a generation after the breakthrough female executive leaves power. Or to put it differently, 10 years after a woman has been a nation’s top executive, it has the same percentage of women in its legislature as does a country in which a woman currently holds power.

Consider the Philippines. During Corazon Aquino’s presidency (1986-1992), only 9 percent of the country’s legislators were women. This figure remained between 10 and 12 percent for a decade after she left office, increasing sharply to 18 percent when the country’s second female president, Gloria Macapagal Arroyo, was elected in 2001. It has since climbed to 27 percent, well above the global average. In nearby Indonesia, only 8 percent of the country’s legislators were women when Megawati Sukarnoputri took office in 2001. This increased to 12 percent by the time she left office in 2004 and has since reached 18 percent.

Of course, we know that average increases don’t mean inevitable increases. In some countries, female leadership has not resulted in having more women in the legislature. For instance, women make up just 17 percent of South Korea’s National Assembly — only 1 percent more than before President Park Geun-hye, the country’s first female head of state, took power in 2013. But on average, having a woman serve as president or prime minister leads to higher numbers of women in the legislature.

Why does having a female president or prime minister result in women in office?

Many countries have only recently elected women as their top leaders. As a result, not much research has been done on what then happens that brings more women into politics.

Here are some possibilities. Having a female president as a model could encourage more women to get politically involved. She could serve as a role model and attract more women to the polls, women who might then be more likely to vote for other women elsewhere on the ticket. By appointing women to cabinet positions — as Clinton has promised to do — a female president could bolster the credentials of those who might run for higher office in the future, or simply inspire women to run.

But will that effect continue? Maybe the additional number of female legislators and cabinet members increases the pool of viable female candidates for high offices for decades to come. Maybe that increase becomes self-perpetuating, as having more female legislators diminishes gender stereotypes, leads people to expect to see both women and men in office, and strengthens the ambitions and credentials of women who may later try for higher office.

Or maybe the shattered glass ceiling gets repaired and replaced as that leader’s legacy fades from political memory. Maybe the processes are different when women are elected as part of a family legacy and when they reach the top office on their own efforts. We just don’t know yet.

But even if electing Hillary Clinton wouldn’t necessarily bring us a second “Madam President” anytime soon, we should expect more women in Congress for at least a decade.

Curtis Bell is research associate at the One Earth Future Foundation’s peace and governance program.