As family structures become more complicated, a new body of new research is attempting to quantify the trend. The proliferation of stepchildren, half-siblings, and other extended relationships has important implications for how American families function.
Almost a third of U.S. households headed by adults under age 55 have at least one stepparent, according to a recent analysis of survey data by University of Massachusetts Boston Professor Emily Wiemers and others. Similarly, the study found that, looking at couples over age 55 who have adult children, 33 percent have a stepchild.
These step-relationships can stretch both the size and definition of family—researchers included both married and unmarried co-habiting couples in the analysis. For Americans with grown children, counting stepchildren boosts the total number of adult kids by 66 percent, the study found.
The rise in divorce and remarriage is driving this growth in family size. Over the past two decades, the divorce rate has doubled for older Americans. Almost 30 percent of people over 50 had been married more than once, according to a recent study by scholars at Bowling Green State University. About 40 percent of older Americans with children are in stepfamilies, according to survey data.