A decades-long rise in non-marital childbearing has stopped climbing and even declined a little since its height near 2005. Demographer Lyman Stone writes:
The share of children born to unmarried moms rose steadily from just 5% in 1960 to about 41% in the late 2000s: then it stopped rising and even declined. While a recent report from Child Trends highlights how high current levels are versus 1990, we are actually approaching a decade of falling births to unmarried moms. Of course, as I’ve argued before, these changes in marital status and childbearing are also driving the fertility rate lower for the whole country. Today, births to unmarried moms have declined enough that they are back below 40% of all births.
In 2016, the share of babies born to unmarried moms fell below 40%, the first time it has been that low since 2007. This is a large social change. Social and family policy in the post-war period incorporated a set of assumptions about what problems would be facing society in the future, particularly rising single-parenthood. The latter half of the twentieth century saw many single-parent-oriented benefits (like the EITC, which is more generous for single parents), aimed at addressing or alleviating the social and economic ills of fragmented families and kids with just one parent.
Today, while progress is slow, that problem is receding. A rising share of kids are born into two-parent homes. This is important for the child, as having two parents in the home is good for child outcomes, but also for adult parents, as being able to share childrearing and work reduces the economic and personal burdens of parenting.