Billionaire and Republican presidential contender Donald Trump, in his latest statements about U.S. immigration reform this week, said American-born children of immigrants living in the U.S. illegally should be denied citizenship. And he reiterated that a wall should be built between Mexico and the United States. The non-partisan Pew Center estimates there are more than 11 million undocumented immigrants in the U.S. - more than half from Mexico and about 25 percent from other Central American countries. But undocumented immigrants and advocacy groups say those without visas should be allowed to stay. VOA’s Deborah Block looks at the controversy.