While you can find a study for pretty much anything these days, people just need to use their logic to recognize what is right and wrong. If we don't accept valid research, we will never progress as a society. Take for instance sugar. There have been studies that have shown that sugar is NOT detrimental to the human body. When you dig deep into this research, you'll find that these studies have been undertaken by researchers on behalf of the sugar industry. Today, most people believe that sugar in large quantities is bad for the body, resulting in obesity, diabetes, cancer, heart disease, etc.
Why do we accept that sugar is bad for us? Because there is clear overwhelming research to show this.
In the same regard, while I agree with you that behavioural problems are multifaceted, one clear indication of behavioural problems is the absence of a father figure in a household. Researchers have proven this over and over and I'm not sure why some (not you personally) are reluctant to even believe this.
Below are some additional studies on this subject.
Fatherless children are at a dramatically greater risk of drug and alcohol abuse, mental illness, suicide, poor educational performance, teen pregnancy, and criminality.
Source: U.S. Department of Health and Human Services, National Center for Health Statistics, Survey on Child Health, Washington, DC, 1993.
High risk. Fatherless children are at dramatically greater risk of suicide.
Source: U.S. Department of Health and Human Services, National Center for Health Statistics, Survey on Child Health, Washington, DC, 1993.
Psychiatric Problems. In 1988, a study of preschool children admitted to New Orleans hospitals as psychiatric patients over a 34-month period found that nearly 80 percent came from fatherless homes.
Source: Jack Block, et al. "Parental Functioning and the Home Environment in Families of Divorce," Journal of the American Academy of Child and Adolescent Psychiatry, 27 (1988)
In a longitudinal study of 1,197 fourth-grade students, researchers observed "greater levels of aggression in boys from mother-only households than from boys in mother-father households."
Source: N. Vaden-Kierman, N. Ialongo, J. Pearson, and S. Kellam, "Household Family Structure and Children's Aggressive Behavior: A Longitudinal Study of Urban Elementary School Children," Journal of Abnormal Child Psychology 23, no. 5 (1995).
Violent rejection: Kids who exhibited violent behavior at school were 11 times as likely not to live with their fathers and six times as likely to have parents who were not married. Boys from families with absent fathers are at higher risk for violent behavior than boys from intact families.
Source: J.L. Sheline (et al.), "Risk Factors...", American Journal of Public Health, No. 84. 1994.
The 'hood The likelihood that a young male will engage in criminal activity doubles if he is raised without a father and triples if he lives in a neighborhood with a high concentration of single-parent families.
Source: A. Anne Hill, June O'Neill, "Underclass Behaviors in the United States," CUNY, Baruch College. 1993