A new report has shed light on the estimated number of births to illegal immigrants on American soil.

The Pew Hispanic Center's study found that 8 percent of children born in the United States in 2008 were born to illegal immigrants. That amounts to one in every 12 births.
   
The non-partisan research group also found there are about 11 million illegal immigrants living in the U.S. and nearly 80 percent of their children - about 5 million - were born here.
    
The study comes as several Republican lawmakers are pushing for a review of the so-called 'birth clause" in the 14th Amendment of in the U.S. Constitution. The clause states that every person born in America is automatically a citizen.

"To have a child in America, they cross the border.  They go to the emergency room, have a child, and that child's automatically an American citizen," Sen. Lindsay Graham, R-S.C., said. "That shouldn't be the case."

"It's a rather unseemly business, and I think we ought to have some hearings and take a look at it," Senate Minority Leader Mitch McConnell, R-Ky., said.

Pew researchers analyzed data based on the Census Bureau's March 2009 population survey.