Teh Maths

And they don't add up.

According to Center for Immigration Studies (CIS) legal policy analyst Jon Feere, who testified before the House Judiciary Committee’s Subcommittee on Immigration and Border Security in April, between 350,000 and 400,000 children are born annually to an illegal-alien mother residing in the United States — as many as one in ten births nationwide. As of 2010, four out of five children of illegal aliens residing in the U.S. were born here — some 4 million kids. Reporting that finding, the Pew Research Center noted that, while illegal immigrants make up about 4 percent of the adult population, “because they have high birthrates, their children make up a much larger share of both the newborn population (8 percent) and the child population (7 percent) in this country.”
The cost of this is not negligible. Inflation-adjusted figures from the U.S. Department of Agriculture projected that a child born in 2013 would cost his parents $304,480 from birth to his eighteenth birthday. Given that illegal-alien households are normally low-income households (three out of five illegal aliens and their U.S.-born children live at or near the poverty line), one would expect that a significant portion of that cost will fall on the government. And that’s exactly what‘s happening. According to CIS, 71 percent of illegal-alien headed households with children received some sort of welfare in 2009, compared with 39 percent of native-headed houses with children. Illegal immigrants generally access welfare programs through their U.S.-born children, to whom government assistance is guaranteed. Additionally, U.S.-born children of illegal aliens are entitled to American public schools, health care, and more, even though illegal-alien households rarely pay taxes.

Let's keep things simple and max it out.

If 400,000 kids are born to illegal aliens, and they're 1 in 10 of the birth rate, then that's 4,000,000 kids total.

71% of illegal kids get some sort of welfare, or 284,000 kids.

39% of legal kids get some sort of welfare, or 1,404,000 kids.

Five times as many legal families get welfare than illegal.

I know the point they're trying to make, and this doesn't make it.

I also note that nearly half of the children born in the US are on "some sort of welfare" too.