Previous research has indicated that divorce poses the greatest threat to family stability and related child well being.
But a new study has revealed that the rise of cohabiting households with children is a greater threat to the quality and stability of children's lives and is also the main reason for the increase of family instability.
The study is co-sponsored by the Centre for Marriage and Families at the Institute for American Values and the National Marriage Project at the University of Virginia.
"In a striking turn of events, the divorce rate for married couples with children has returned almost to the levels we saw before the divorce revolution kicked in during the 1970s. Nevertheless, family instability is on the rise for American children as a whole," said W. Bradford Wilcox, National Marriage Project director and the study's lead author.
"This is mainly because more couples are having children in cohabiting unions, which are very unstable. This report also indicates that children in cohabiting households are more likely to suffer from a range of emotional and social problems - drug use, depression and dropping out of high school - compared to children in intact, married families," he added.