There's no doubt that sociological trends have played a role in the changing face of our society and of the American family in the late-20th and early-21st centuries. Advances in racial and marriage equality; feminism and women leaving the home to join the workforce in droves; less of a stigma attached to single parenthood, divorce and "non-traditional" family structures. These have all contributed to fewer people getting married, more opting for divorce (especially in middle age), and more American adults (and mothers) than ever checking off the "single" box on their tax forms.
But current research shows that the state of the economy has been the primary driver in changing family dynamics since 1990. As we emerge from the worst economic downturn since the Great Depression, some trends are self-evident, with others not as obvious: Less job security results in greater family insecurity.
The costs of raising kids and higher education have risen dramatically over the past two generations. But, at the same time that single couples have been postponing getting married and having children for economic reasons, the divorce rate has continued to climb, as has the number of single mothers.