In a surprising finding, a government-funded study released Tuesday said children in immigrant families experience fewer health problems and injuries than do children of U.S-born parents despite a higher rate of poverty and less health insurance.

There are 14 million children under 18 who are immigrants them-selves or the children of newcomers. Immigrant children are three times as likely as the children of U.S.-born parents to lack health insurance, while second-generation children are twice as likely to lack health coverage, according to the study by a panel of experts convened by the National Research Council and the Institute of Medicine.Immigrant children are more likely to be poor and less likely to live in households receiving public assistance.

Yet these immigrant families tend to have fewer low-birthweight babies and infant deaths, while their teenagers report fewer mental health problems and incidences of risky behavior, such as drinking and smoking, the study said.

The researchers acknowledged that data on immigrants kids was "disturbingly sparse" and offered no definitive reason why these children appear healthier.

But advancing one theory, the panel said immigrant children may be temporarily shielded from "many of the deleterious health consequences that typically accompany poverty, minority status and other indicators of disadvantage in the United States."

For example, they cited immigrant mothers' comparatively low levels of smoking, alcohol and drug consumption during pregnancy, as well as healthier diets and supportive family networks.

Over time, however, the health advantages of the immigrant children vanish, according to the book-length report, "From Generation to Generation: The Health and Well-being of Children in Immigrant Families."