SAN JOSE -- A bill that would end birthright citizenship in the U.S. is gaining steam in Washington, thanks to the Republican Presidential campaign.

It targets a controversial underground industry known as birth tourism, pregnant foreign women traveling to this country just for the purpose of delivering American citizen babies.

Business is booming here in the Bay Area, especially in the South Bay.

But publicity is not welcome.

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"I don't have a comment, I don't have a comment," said Jerry Zhou. He runs a popular tourist agency. The destination, not Fisherman's Wharf, or the Golden Gate Bridge, but a regular home on a residential street in North San Jose.

We've learned the home is actually a birthing hotel. It caters to pregnant women, mostly from China, who come to the U.S. to grab that prize: instant U.S. citizenship for their baby.

Neighbor Robert Ramos says the women keep a low profile, rarely walking the neighborhood, going in and out only in a van with tinted windows. But he says what's going on inside is pretty obvious.

"At one time I think there were four -- four of them at the same time," he said. "It's pretty predictable, you can see when somebody's giving birth. You don't see them afterwards, and then a new family comes in."

The house is one of at least two locations run by Jerry Zhou, who advertises on the internet under the name California Baby Care. For $3,000 to $4,000 a month everything's included: dedicated nannies, professional chefs, transport to- and from the hospital, and a passport for the newborn.

"There's a business apparently established apparently to do this. I think it's fraud," said Ramos.

Homeland security cracked down on a similar operation in Southern California earlier this year.

ICE agents raided three addresses where they found dozens of women from China, either pregnant or who had just given birth.

The crackdown is prompting debate on Capitol Hill on whether to end birthright citizenship.

A new bill would allow it only for children of citizens or legal U.S. residents.

"The organizers of these birth tourist hotels have figured out how to game the system," said Jon Feere with the Center for Immigration Studies, a conservative research foundation.

"If you tell our visa processors that you are here to visit Disneyland when in reality you are here to give birth, that does constitute fraud," Feere said.

But Bill Hing, an immigration law professor at the University of San Francisco disagrees.

"There is no regulation that prohibits a woman from coming to the U.S. to give birth," said Professor Hing, after reviewing the affidavits.

Hing says the birth hotel operators may get fined for tax violations, but that's about all.

"It's not viable in terms of real law, but it has political viability. It appeases their constituents that are anti-immigrant," Hing said.

Back in San Jose, Jerry Zhou didn't want to discuss the matter and denied having anything to do with babies or pregnant women.

"This house is on your website. It's advertised on your website as a birth hotel, that is why we are here," KPIX reporter Betty Yu told him. Zhou's response: "I don't know what you are talking about. I don't have any comment."

Homeland Security also did not want to comment on the story, telling KPIX 5 their investigation in Southern California is still ongoing. Word on the street here is that the crackdown down south has pushed many of the operations up north