It's called "maternity tourism."
Pregnant women travel to the United States, usually on tourist visas, so that their children will be born U.S. citizens. In Southern California, they often live with other pregnant women in suburban homes.
Maternity tourism is particularly popular with wealthy women from China.
The practice is getting new attention after GOP presidential candidate Jeb Bush on Monday tried to explain that his controversial comments about "anchor babies" were "more related to Asian people," who he said were committing fraud in order to "take advantage of a noble concept, which is birthright citizenship."
Bush did not mention maternity tourism. But the controversial industry has been in the news in recent years. Neighborhood groups have complained about so-called "birthing centers" in residential neighborhoods.
How big is this industry?
It's hard to know.
Earlier this year, Immigration and Customs Enforcement launched a major crackdown in Southern California.
FOR THE RECORD
Aug. 26, 3:25 p.m.: An earlier version of this post referred to a crackdown earlier this year by the FBI. The agency that launched the crackdown was Immigration and Customs Enforcement.
One affidavit related to that case quoted a law review article estimating that about 40,000 of 300,000 children born to foreign citizens in the U.S. each year are the product of birth tourism.
The website of one birthing center suggested that 4,000 Chinese women had been served since 1999.
The crackdown included one birthing center in Irvine. According to an affidavit, more than 400 women associated with the Irvine location have given birth at one Orange County hospital since 2013. One of the women paid $4,080 out of $28,845 in hospital bills, while her bank account showed charges at Wynn Las Vegas and purchases at Rolex and Louis Vuitton stores, the affidavit said.
Is this illegal?
The sweeps were looking for evidence of tax evasion, money laundering by the operators as well as immigration fraud.
In March, swarms of agents descended on homes and apartment complexes in Los Angeles, Orange and San Bernardino counties, carting out boxes of documents, diaper containers and trash, and interviewing pregnant women to the backdrop of wailing babies.
Investigators said they were looking for evidence of visa fraud, conspiracy and other crimes in which women were helped to fabricate documents for visa applications and coached to falsely claim that they were traveling to the U.S. for tourism. Women were instructed to travel early in their pregnancy and wear loose clothing to avoid detection, and enter the U.S. through popular tourist destinations rather than Los Angeles, where authorities are more likely to suspect birth tourism, according to the affidavits.
In May, federal agents arrested an Irvine attorney on suspicion of trying to spirit a Chinese woman out of the U.S. in violation of a court order that she remain in the country as part of an investigation into the illegal immigration of pregnant women.
Have officials cracked down on the maternity homes?
In 2013, following a flurry of complaints, Los Angeles County inspectors cited 16 "maternity hotel" owners for illegally operating boardinghouses in residential zones. They were located mostly in Rowland Heights and Hacienda Heights.
Residents also have complained about the centers in Chino Hills, Lancaster, Irvine and elsewhere.