Travelling to another country for medical procedures, or medical tourism, is a growth industry both as an export and an import. U.S. citizens may travel for medical treatments that are less expensive and patients with means come to the U.S. for high-quality services that may not be available abroad. Paying full cost for the services provides a healthy stream of income for some U.S. healthcare facilities.

But high-quality medical treatment is not the only attraction for a particular type of medical tourist. As one of a few countries that grants citizenship to any person born on American soil, a cottage industry has developed around birth tourism. Pregnant women by the thousands from countries that includes China, Taiwan, Saudi Arabia, South Korea, Nigeria, Turkey, Russia, Brazil, and Mexico come to the U.S. every year to give birth to U.S. citizens.

Although President Donald Trump has railed against “anchor babies,” there is no law that prohibits foreign nationals from coming to the U.S. to give birth, although many end up committing immigration fraud by misrepresenting the purpose of their visits to gain entry or obtain an appropriate visa.

Some who come to the U.S. to give birth find themselves in less than ideal situations (in terms of housing and medical care) and may even be putting their babies at medical risk. But, for the wealthy among them, birth tourism can be a luxurious semi-vacation and an investment in the future for their children and their families. Spending up to $80,000 for birth tourism packages advertised online, these mothers-in-waiting also visit shopping centers and restaurants and contribute to the economy in the areas where they congregate, particularly in California, New York, and Florida.

U.S. officials, however, are cracking down on the birth tourism industry for tax fraud, contractual breaches, immigration fraud (helping birth tourists get visas under false pretenses), and even zoning violations. ICE officials have raided “birth hotels” in California and has been reported that at Los Angeles International Airport, CBP has been tightening security particularly for pregnant Chinese women who are trying to enter the country.

One of the biggest advantages of having a U.S. citizen child is that once that child reaches the age of 21, he or she could sponsor for a Green Card the parents who “gave” the child U.S. citizenship in the first place. That family unity benefit, called “chain migration” by Trump, is another one of the immigration programs that Trump would like to eliminate.