FWIW:
According to the U.S. Census, the poverty rate for single parents with children in the United States in 2008 was 36.5 percent. The rate for married couples with children was 6.4 percent. Being raised in a married family reduced a child’s probability of living in poverty by about 80 percent.[1] (See Chart 1.)
Some of this difference in poverty is due to the fact that single parents tend to have less education than married couples, but even when married couples are compared to single parents with the same level of education, the married poverty rate will still be more than 75 percent lower. Marriage is a powerful weapon in fighting poverty. In fact, being married has the same effect in reducing poverty that adding five to six years to a parent’s level of education has.[2]
When compared to children in intact married homes, children raised by single parents are more likely to have emotional and behavioral problems; be physically abused; smoke, drink, and use drugs; be aggressive; engage in violent, delinquent, and criminal behavior; have poor school performance; be expelled from school; and drop out of high school.[19] Many of these negative outcomes are associated with the higher poverty rates of single mothers. In many cases, however, the improvements in child well-being that are associated with marriage persist even after adjusting for differences in family income. This indicates that the father brings more to his home than just a paycheck.
The effect of married fathers on child outcomes can be quite pronounced. For example, examination of families with the same race and same parental education shows that, when compared to intact married families, children from single-parent homes are:
• More than twice as likely to be arrested for a juvenile crime;[20]
• Twice as likely to be treated for emotional and behavioral problems;[21]
• Roughly twice as likely to be suspended or expelled from school;[22] and
• A third more likely to drop out before completing high school.[23]
The effects of being raised in a single-parent home continue into adulthood. Comparing families of the same race and similar incomes, children from broken and single-parent homes are three times more likely to end up in jail by the time they reach age 30 than are children raised in intact married families. [24] Compared to girls raised in similar married families, girls from single-parent homes are more than twice as likely to have a child without being married, thereby repeating the negative cycle for another generation
http://www.heritage.org/Research/Reports/2010/09/Marriage-America-s-Greatest-Weapon-Against-Child-Poverty