(NewsNation) — Author Melissa Kearney has received both praise and criticism for highlighting in her new book that children raised by married parents tend to experience better outcomes than those from alternative family structures. 

This underscores a significant issue within the United States, where 23% of American children live with a single parent, without the presence of any other adults, nearly three times higher than the global average. 

Bradley Wilcox, who himself was raised by a single mother and now serves as the director of the National Marriage Project, told NewsNation’s Leland Vittert in a Monday “On Balance” interview that until the late 1960s and 70s, the vast majority of children grew up with both of their parents unless a tragic event such as the death of a parent occurred.

Vittert recognized the complexities of this issue, acknowledging that women sometimes leave abusive relationships to protect themselves and their children. “Most mothers are not single moms, necessarily by choice,” Vittert said. 

In the book, Kearney contends that the marital status of parents significantly influences the success of their children. But this idea has received significant backlash. 

Wilcox addressed the issue by emphasizing that marriage has been erroneously branded as a conservative or traditional concept, linked to religious and political affiliations.  

“Unfortunately, marriage has become coated as a kind of a conservative issue, as a traditional issue,” Wilcox said. 

Research shows that children thrive in intact married families, and the institution of marriage has been a universal aspect across nations, cultures and history. It’s not exclusive to any group, according to Wilcox. 

In 2021, 40% of all U.S. babies were born to unmarried mothers, marking a significant increase from the 18% in 1980, according to Statista. 

Wilcox pointed out, however, that there has been a plateau in these trends since 2009, with nearly two-thirds of children now being raised in stable married families.