Nearly half of adult immigrants in the U.S. illegally today are parents of minor children, according to new research by the Pew Hispanic Center.

Additionally, nearly two-thirds of the 10.2 million unauthorized adult immigrants in the United States have lived in this country for at least 10 years.

Both statistics have significant implications when considering plans put forth by Republican candidates jostling for the 2012 GOP presidential nomination.

In particular, Newt Gingrich has endorsed a plan to create a path for unauthorized immigrants to gain legal status if they have lived in the country for a long period of time, have children in the U.S., pay taxes and belong to a church.

"Because I think we are going to want to find some way to deal with the people who are here to distinguish between those who have no ties to the United States, and therefore you can deport them at minimum human cost, and those who, in fact, may have earned the right to become legal, but not citizens,” said Gingrich while in Iowa this past May.

His opponents have criticized the proposal as a form of amnesty that would encourage more immigrants to come to the U.S. illegally.

“You’ve got to get rid of the incentives. No amnesty. No forced benefits,” said Ron Paul, speaking at the 2008 Republican primary debate at St. Anselm College in New Hampshire. “It just won’t work if you try to see this in a vacuum. You have to deal with it as a whole, as an economic issue as well.”

Ex-Massachusetts Gov. Mitt Romney told Fox News in November he was against Gingrich’s plan.

"If he's going to do what I believe he said he was going to do for those people who would be allowed to stay permanently and become citizens, that would be providing for them a form of amnesty," Romney said.

“There's great interest on the part of some to talk about what we do with the 11 million. My interest is saying, let's make sure that we secure the border, and we don't do anything that talks about bringing in a new wave of those or attracting a new wave of people into the country illegally,” Romney added.

The Pew results are based on data from the U.S. Census Bureau’s March 2010 Current Population Survey, augmented with the Center’s analysis of the demographic characteristics of the unauthorized immigrant population using a “residual estimation methodology” that the Center has employed for many years.