The family system of the United States is often characterized as consisting of nuclear-family households—that is, households consisting of no more than the parent(s) and dependent children, if any (Lee 1999). This is certainly true of the great majority of family households. In fact, there has never been a point in American history in which extended-family households predominated statistically (Ruggles 1994a; Seward 1978). In 1997 only about 4.1 percent of all families in the United States were "related subfamilies"—a married couple or single parent with children living with a related householder (U.S. Bureau of the Census 1998, Table 69). However, an analysis of census data from 1970 through 1990 by Glick and colleagues (1997) showed that the percentage of all households containing nonnuclear kin increased from 9.9 percent in 1980 to 12.2 percent in 1990, reversing a nearly century-long pattern of decline. In 1910 about 20 percent of the households of white families...