Final answer:
The number of one-child families in the United States accounts for approximately 20 percent of American families. This reflects the changing dynamics of family structures, including the rise of single-parent and cohabitating parent households.
Step-by-step explanation:
The number of one-child families continues a steady increase, making up about 20 percent of American families. This increase is indicative of a broader trend surrounding family structures in the United States.
According to recent statistics, more than one-quarter of U.S. children live in a single-parent household, and the notion of the nuclear family with a married couple and children has seen a decline. For instance, 32 percent of children lived with a single parent only in 2017, which demonstrates an increase from previous years.
While the demography of American households has changed over the years, two-parent households are still the most common, despite the significant decline from past decades. As family structures evolve, so do societal norms and expectations surrounding what constitutes a family unit. This evolution is also reflected in the number of children living with cohabitating parents, which has been rising in recent years.