Birth tourism is becoming a trend in Los Angeles County, where 60 alleged maternity hotels were reported in the past month, the county planning department told ABC Nightline.

Websites advertise these maternity hotels to women from Asia, offering them the opportunity to give birth in the U.S. so their children could be American citizens, Nightline reported. It's not illegal for these mothers to come to the U.S. to give birth, because the 14th Amendment grants citizenship to all those born or naturalized in the county.

"This is the sort of thing the government winks at," David North, a researcher with the non-partisan Center for Immigration Studies told Nightline. "It's just one more of the elements in which the American immigration policy is an open door situation."

But there's another problem. Authorities have had difficulties accessing the hotels, Nightline reported, but three out of the seven they did inspect were in violation of zoning codes.  Recently, a campaign sought to close a "maternity mansion" with 14 complaints over a period of five years in San Bernardino County, according to a Jan. 14 report cited on Nightline.

"We are trying to make sure every house is in compliance with the zoning ordinance," Alex Garcia, a supervising regional planner at the Los Angeles Department of Regional Planning, told Nightline. "These recovery homes do what they're going to do and as long as we see they're in compliance, then we don't go and crack down on them."

Of the 60 complaints, all but one of these hotels were located in areas where boarding houses are prohibited, according to a report by Los Angeles County officials referred to on Nightline. But most of the hotels look like houses from the outside, and without access, it's hard for planning officials to do anything, Nightline reported.

Los Angeles County Supervisor Don Knabe told The South China Morning Post that he asked his colleagues to approve a process aimed at closing hotels - mainly the ones in which single-family homes were illegally divided into at least a dozen bedrooms.

"They're a moneymaking machine," Knabe told The South China Morning Post. "They're totally unsafe. It's so obvious that they jeopardize not only the health of the baby, but the mother as well."

But South California immigration activists argued that the whole controversy may have been fueled by the national illegal immigration debate.

"If you've got a home and it's unsafe for one reason or another, you certainly want a public safety interaction making the place safer," Dr. Manuel Pastor, a professor of sociology at the University of Southern California told The South China Morning Post. "But this is playing out against the terrain of pretty heated immigration politics that's likely to get even more heated in next few months," Pastor said.