If American Catholicism has an Achille’s heel, it’s sometimes an attenuated sense of how we fit into the rest of the Catholic world. A bit of basic math will help explain why that’s a problem.

As of early 2017, there were just under 1.3 billion Catholics in the world, and around 70 million in the United States. While that makes us the world’s fourth largest Catholic nation, after Brazil, Mexico and the Philippines, it also means that we represent less than six percent of the global Catholic population.

Put another way, 94 percent of the Catholics in the world aren’t like us.

Two-thirds of those 1.3 billion Catholics now live outside the West, a share that will be three-quarters by mid-century. There are twice as many Catholics today in sub-Saharan Africa as in North America, a gap that swells with every passing day, and nearly twice as many in Asia.

Based on that, here’s a core insight about Catholic life in the early 21st century: American experiences, priorities and perspectives cannot always set the tone, because not everyone sees the world the same way we do, and increasingly, we’re not the big dogs anymore.

All this comes to mind in light of a new study released this week in advance of the March 8-14 National Catholic Sisters Week, showing there are now more than 4,000 foreign-born nuns studying or serving in the United States, part of a “reverse mission” from the Third World to the First.

On average, according to the findings, these sisters are substantially younger than the American average, and also highly educated, with 73 percent holding at least a bachelor’s degree. Asia is the largest sending continent, but the sisters come from all over.

That’s on top of what we already know about the swelling presence of foreign-born priests in the United States. Today, roughly, one-fourth of all diocesan priests in the U.S. come from foreign countries, and three in ten American priests ordained in 2016 were born outside the country.

Statistically speaking, it’s clear that the future of pastoral ministry in the U.S. is increasingly going to be in the hands of non-native Americans.

At times, these trends generate alarm among some American Catholics. Some worry that we’re dropping the ball in terms of responsibility for generating our own vocations, while others complain that foreign priests and sisters sometimes don’t adjust well to American cultural expectations and can be a bad fit at the grassroots level.

My late Grandma, for instance, would sometimes grumble that she had a hard time understanding her Donum Fidei priest from Myanmar, who was serving as pastor of her tiny Western Kansas parish which otherwise would have become a circuit-rider outpost a long time ago, because of his foreign accent. (In reality, she stubbornly refused to upgrade her hearing aids and frankly couldn’t understand anybody, including me most of the time.)

Still others worry that an increasing dependence on foreign priests and nuns may fuel a “brain drain” from churches in the developing world, siphoning off personnel from places that need those human resources far more than we do.

All, in principle, are valid concerns. American Catholics obviously should be encouraging native-born vocations, we need to promote cultural adjustment by foreign-born ministers serving here, and we also need to be careful not to exploit the material poverty of local churches in other parts of the world to satisfy our own desires.

Cardinal John Onaiyekan of Abuja, Nigeria, never one to mince words, once gave me a vintage way of phrasing that last point. He was talking about Europe, but he just as easily could have been discussing the United States.

“What we don’t want is to get into a Gastarbeiter situation, where a European priest feels overwhelmed having to say three Masses on Sunday, and so he wants a black man to say them,” Onaiyekan said. “Surely this is not where the Church wants to go, getting poor people to do jobs that the rich don’t want to do, as today happens in other walks of life.”

Yet there’s also a tremendous upside to the growing presence of foreign-born sisters and priests serving in the country.

First of all, there’s the obvious point that in many ways, the Church here would come grinding to a halt without them. They help keep our parishes, schools, hospitals, and other Catholic institutions not only afloat, but dynamic and vital.

Beyond that, they’re also ambassadors of the other 94 percent of the Catholic world in our midst. They can inform our debates about things we already care about, but also help us understand why our obsessions aren’t necessarily those of the rest of the Catholic world.

Among many other things, they can help us understand what anti-Christian persecution actually means – not just nativity sets dislodged from courthouses or wrangles over insurance coverage, but what it means literally to take your life in your hands every time you set out for church on Sunday. They can offer different perspectives on the conversations we’re already having, with Amoris Laetitia being a great example, and also open our eyes to why those issues sometimes strike much of the rest of the Catholic world as incredibly insular.

Naturally, there are things foreign-born clergy and sisters can learn from the American church too. Best practices on money management and anti-abuse efforts, which sometimes lag behind in other countries, are merely two compelling for-instances.

The bottom line, however, is that the presence of foreign-born nuns and priests offers American Catholicism perhaps the single greatest opportunity for faith formation about life in the Church in the 21st century we could ever dream of summoning.

Here’s hoping we have the imagination to take advantage.