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MIAMI — Lured by the charm of little Havana or the glamour of South Beach, some 15 million tourists visit Miami every year.

But for a growing number of Russian women, the draw isn't sunny beaches or pulsing nightclubs. It's U.S. citizenship for their newborn children.

In Moscow, it's a status symbol to have a Miami-born baby, and social media is full of Russian women boasting of their little americantsy.

"It's really common," said Ekaterina Kuznetsova, 29. "When I was taking the plane to come here, it was not only me. It was four or five women flying here."

Ekaterina was one of dozens of Russian birth tourists NBC News spoke to over the past four months about a round-trip journey that costs tens of thousands of dollars and takes them away from home for weeks or months.

Why do they come?

"American passport is a big plus for the baby. Why not?" Olesia Reshetova, 31, told NBC News.

"And the doctors, the level of education," Kuznetsova added.

The weather doesn't hurt, either.

"It's a very comfortable place for staying in wintertime," Oleysa Suhareva said.

Oleysa Suhareva traveled from Russia to Miami to give birth. Courtesy Oleysa Suhareva

It's not just the Russians who are coming. Chinese moms-to-be have been flocking to Southern California to give birth for years.

What they are doing is completely legal, as long as they don't lie on any immigration or insurance paperwork. In fact, it's protected by the 14th amendment to the U.S. Constitution, which says anyone born on American soil is automatically a citizen.

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The child gets a lifelong right to live and work and collect benefits in the U.S. And when they turn 21 they can sponsor their parents' application for an American green card.

As president, Donald Trump has indicated he is opposed to so-called chain migration, which gives U.S. citizens the right to sponsor relatives, because of recent terror attacks. And as a candidate, he called for an end to birthright citizenship, declaring it in one of his first policy papers the "biggest magnet for illegal immigration."

"You have to get rid of it," he said on "Meet the Press" on NBC. "They're having a baby and all of a sudden — nobody knows — the baby is here. You have no choice."

In a twist, as the Daily Beast first reported, condo buildings that bear the Trump name are the most popular for the out-of-town obstetric patients, although the units are subleased from the individual owners and it's not clear if building management is aware.

There is no indication that Trump or the Trump Organization is profiting directly from birth tourism; the company and the White House did not respond to requests for comment.

Roman Bokeria, the state director of the Florida Association of Realtors told NBC News that Trump- branded buildings in the Sunny Isles Beach area north of Miami are particularly popular with the Russian birth tourists and Russian immigrants.

"Sunny Isles beach has a nickname — Little Russia — because people who are moving from Russian-speaking countries to America, they want … a familiar environment."

"They go across the street, they have Russian market, Russian doctor, Russian lawyer," he added. "It's very comfortable for them."

Oleysa Suhareva's baby became an American citizen by being born in Miami. Courtesy Oleysa Suhareva

Reshetova came to Miami to have her first child, hiring an agency to help arrange her trip. The services — which can include finding apartments and doctors and obtaining visas — don't come cheap. She expects to pay close to $50,000, and some packages run as high as $100,000. Bokeria says some landlords ask for six months rent up front.

One firm, Miami Mama, says it brings about 100 Russian and Russian-speaking clients to the U.S. per year, 30 percent of them repeat clients. The owners are Irina and Konstantin Lubnevskiy, who bought Miami Mama after using the firm to have two American children themselves.

The couple says they counsel clients to be completely transparent with U.S. immigration officials that they're expecting.

"We tell every client, 'You have the documents, you have to tell the truth. This is America. They like the truth here,'" Konstantin said.

"I would like the American people to understand they don't have to worry," he added. "Those who come here want to become part of the American people."

But Miami Mami has drawn scrutiny from law enforcement. In June, it was raided by the FBI, and an employee was convicted of making false statements on passport applications. The owners say they knew nothing about it, fired the worker and their business license was renewed.

Federal prosecutors declined to comment on the case, and the FBI said it could not discuss "an active investigation."

There is no official data on birth tourism in the United States. The Center for Immigration Studies, which wants stricter limits on immigration, estimates there are 36,000 babies born in the U.S. to foreign nationals a year, though the numbers could be substantially lower. Florida says births in the state by all foreign nationals who live outside the United States have jumped 200 percent since 2000.

Customs and Border Protection says there are no laws governing whether pregnant foreign nationals can enter the country or give birth here.

"However, if a pregnant woman or anyone else uses fraud or deception to obtain a visa or gain admission to the United States, that would constitute a criminal act," the agency said.

When federal agents raided California "maternity hotels" catering to Chinese clients in 2015, authorities said in court papers that some of the families falsely claimed they were indigent and got reduced hospital rates.

In Miami, the Jackson Health System said 72 percent of international maternity patients — who represented 8 percent of all patients giving birth last year — pay with insurance or through a pre-arranged package.

Reshetova said she understands the concerns some have about birth tourism, because it's also an issue in Russia.

"But I pay by myself," she said. "I pay with my money, bring it here to America. I'm not going to take something to America.

"I don't know what my daughter will choose in future. But if I can spend money — my money — for her choice, why not?"

Cynthia McFadden and Sarah Fitzpatrick reported from Miami, and Tracy Connor from New York. Anna Schecter contributed reporting from New York, and Natasha Lebedeva from Washington.