by Steven A. Holmes

About the author: Steven A. Holmes is a staff writer for the New York Times.

Fueled by immigration and higher birth rates among Hispanic women, the United States is undergoing a profound demographic shift, and by the middle of the twenty-first century only about half of the population will be non-Hispanic whites, the Census Bureau predicted in March 1996.

By 2050, the bureau said, immigration patterns and differences in birth rates, combined with an overall slowdown in growth of the country’s population, will produce a United States in which 53 percent of the people will be non-Hispanic whites, down from 74 percent in the mid-1990s.

In contrast, Hispanic people will make up 24.5 percent of the population, up from the current 10.2 percent, and Asians will make up 8.2 percent, an increase from the...