Claudia Gaitan cleans houses for a living in South Florida and supports four children, three of whom were born in Miami after the Nicaraguan woman arrived illegally in the United States five years ago.

Gaitan, 29, says she came to the U.S. to follow her husband, who had come here earlier, escape poverty at home and send money to her family back in Nicaragua. Having children here was not a factor in her journey, she said.

"It never crossed my mind as the reason," said Gaitan during an interview Wednesday with El Nuevo Herald.

But Gaitan giving birth to three daughters in Miami has put the her family -- and millions of other undocumented families with American-born children -- at the center of a growing debate about whether to deny citizenship to children born to illegal parents.

As the debate swirls, the respected Pew Hispanic Center in Washington on Wednesday released a new study saying that at least four million children born in the United States belong to undocumented parents.

Other findings in the Pew report, based partly on U.S. Census data:

• In 2009, immigrants -- legal or illegal -- made up 12.8 percent of the total U.S. population.

• 37 percent of all adult undocumented immigrants were parents of U.S. citizen children.

Whether to deny citizenship to U.S.-born children of undocumented immigrants is the new battleground in the rekindled immigration debate between those who oppose illegal immigration and those who favor an immigration overhaul.

The Department of Homeland Security's Office of Immigration Statistics has estimated at 10.8 million the number of undocumented immigrants currently in the country.

Of the four million children, an estimated 340,000 were born in 2008, according to the Pew study released Wednesday as a way to inform the debate which focuses on possibly modifying the U.S. Constitution's 14th Amendment, adopted in 1868.

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