Illegal immigrants give birth to about 1 in 12 babies born on U.S. soil, a number that far outstrips the proportion of the population they represent.
Immigrants without legal standing to be in the U.S. represent about 4% of the population, but their children represent 8% of total U.S. births, a new report from the Pew Hispanic Center estimates.
The numbers could fuel the debate about whether to continue granting U.S. citizenship to all children born on U.S. soil. Some senators are exploring the idea, but it would be hard to ban the practice. Citizenship by birthright is granted under a constitutional amendment, and overturning it would require winning over two-thirds of Congress and three-quarters of state legislatures.
Some worry that illegal immigrants drain public resources; others argue that low-skilled immigration improves productivity and bolsters the economy overall.
The Pew researchers based their study on the 4.8 million children born in the U.S. in 2008.