If anyone wants to know why Western countries import so many migrants from the Third World, the answer may lie in the cultural norms that have dominated over the past 50 years.

Women are expected to go to college, become professionals in the work force, and "contribute" to the national economy.

But, as many of these countries are now discovering, the female contributions come with a cost.

With women having fewer babies, there comes a point when there are not enough worker bees to support the growing number of elderly who retire every year in countries like Germany, Italy, Greece and Spain.

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All of these countries have dismal fertility rates of between 1.3 and 1.5 children per woman of child-bearing age. Sweden, the U.K. and the U.S. are not much better at 1.8 children per woman.

Economists agree that any nation with a fertility rate of less than 2.1 children per woman will not replace its aging population and ultimately fall into decline. Unless, they say, the nation uses immigration to make up for its birth dearth.

In 2016 America's fertility rate fell to its lowest point on record, and in 2017 it stands at a frightfully low rate of 1.87 babies per woman. But the country's population continues to increase because of historically high rates of immigration.

One country, Poland, has decided to try another route to reversing its paltry 1.35 fertility rate.

Rather than importing a younger work force from Africa or the Middle East, which is seen by some conservatives as a highway to national suicide, Poland has kicked off a national fertility campaign where it encourages its own women to have more babies.

The predominantly Catholic country is being blasted by critics on the left for its new ad campaign that compares a healthy lifestyle for fertility to that of rabbits.

Watch Poland's new video ad campaign encouraging Polish women to have more babies:

"I know what I'm talking about," says the rabbit in the video. "My dad had 63 of us!"

While it may seem comical to some, and even gets mocked as "sexist" and "racist" by radical feminists, the demographics don't lie, says Ann Corcoran, who follows the global movement of populations through her blog, Refugee Resettlement Watch.

If Western nations do not turn around dwindling birth rates soon the entirety of Western civilization will be caught in a "death spiral" that is impossible to reverse, said Corcoran, referencing Mark Steyn's seminal 2008 book "America Alone: The End of the World as We Know It," which predicted the fall of Europe to Islam.

But since Steyn's book was published nearly 10 years ago, the United States has descended into its own demographic winter.

"The declining birthrates really are the basis that our politicians give for justifying mass immigration," Corcoran noted.

The United Nations acknowledged the demographic crisis in a 2000 document titled "Replacement Migration: Is it a Solution to Declining and Aging Populations?" In that screed, the U.N. suggested a controversial solution to the low-birth-rate woes of 10 major nations – mass migration. Among the 10 listed as facing demographic decline if they don't import younger migrants are the U.S., Germany, Italy, the United Kingdom, Russia, South Korea and Japan.

Former Florida Gov. Jeb Bush cited the need for replacement migration as the reason for his advocacy of open-borders policies during a November 2013 interview with 92nd Street Y.

Economic growth "is not sustainable," Bush said, without mass migration from the Third World.

Watch 1-minute clip of Jeb Bush pushing the U.N. globalist solution to America's declining birth rate:

The hypocrisy of global elites

Yet, isn't it the same globalist elites who have been encouraging Westerners for decades to have smaller families who are now whining about a lack of young workers coming into the work force?

"Europeans aren't having babies, Americans aren't having babies," Corcoran said. "It has been drummed into the heads of American college girls since the early 1970s that we should only have two children because of the growing world population. But who never listened to this propaganda? Pretty much all of the Third World and the Islamic world."

See every nation's fertility rate.

Across the board, studies show the more educated a country's women become, the fewer children they have. The reasons why this is so may vary, depending on the author of the study, but the empirical data does not vary.

In order for a generation to replace itself, the fertility rate must be 2,100 births per 1,000 women, or 2.1 births per woman. The U.S. has been missing that mark since 1971, though the country’s population has grown because of rising immigration – both legal and illegal – which is used by governments to fill in the population gaps left by the growing numbers of professional women who have only one or two children, or no children at all.

Rep. Steve King, R-Iowa, got in trouble with the media when he stated the obvious in a tweet last March.

King's tweet was in support of the Dutch anti-Islam politician, Geert Wilders:

Wilders understands that culture and demographics are our destiny. We can't restore our civilization with somebody else's babies. https://t.co/4nxLipafWO — Steve King (@SteveKingIA) March 12, 2017

King also tweeted his support for conservative German candidate Frauke Petry.

@FraukePetry Wishing you successful vote. Cultural suicide by demographic transformation must end. @geertwilderspvv pic.twitter.com/Kp6uieaMDG — Steve King (@SteveKingIA) September 18, 2016

The response from Democrats and establishment Republicans was swift, with accusations that he was "openly peddling white nationalism."

Jeb Bush was also upset by King's tweet, responding with a tweet of his own that read:

America is a nation of immigrants. The sentiment expressed by Steve King doesn't reflect our shared history or values. https://t.co/msydFudA7m — Jeb Bush (@JebBush) March 13, 2017

The left-leaning Salon reported it this way: "The text [demographic transformation] is a reference to a racist tenet – common among white nationalists and fascists – that people of color, immigrants and Muslims pose a threat to 'white purity.'"

Globalists can't have it both ways: Encouraging family planning, more women climbing the career ladder and having fewer children, then complaining about the aging population and smearing the reputations of everyone who balks at the idea of seeing their city, their state, their nation transformed into an Islamic enclave.