New research provides confirmation of a decades-old theory: children raised by authoritarian parents are more likely to grow up into right-wingers.

Parents: Do you find yourselves arguing with your adult children over who deserves to win the upcoming election? Does it confuse and frustrate you to realize your political viewpoints are so different?

Newly published research suggests you may only have yourself to blame.

Providing the best evidence yet to back up a decades-old theory, researchers writing in the journal Psychological Science report a link between a mother’s attitude toward parenting and the political ideology her child eventually adopts. In short, authoritarian parents are more prone to produce conservatives, while those who gave their kids more latitude are more likely to produce liberals.

This dynamic was theorized as early as 1950. But until now, almost all the research supporting it has been based on retrospective reports, with parents assessing their child-rearing attitudes in hindsight.

This new study, by a team led by psychologist R. Chris Fraley of the University of Illinois at Urbana-Champaign, begins with new mothers describing their intentions and approach in 1991, and ends with a survey of their children 18 years later. In between, it features an assessment of the child’s temperament at age 4.

The study looked at roughly 700 American children and their parents, who were recruited for the National Institute of Child Health and Human Development’s Study of Early Child Care and Youth Development. When each child was one month old, his or her mother completed a 30-item questionnaire designed to reveal her approach to parenting.

Those who strongly agreed with such statements as “the most important thing to teach children is absolute obedience to whoever is in authority” were categorized as holding authoritarian parenting attitudes. Those who robustly endorsed such sentiments as “children should be allowed to disagree with their parents” were categorized as holding egalitarian parenting attitudes.

When their kids were 54 months old, the mothers assessed their child’s temperament by answering 80 questions about their behavior. The children were evaluated for such traits as shyness, restlessness, attentional focusing (determined by their ability to follow directions and complete tasks) and fear.

Finally, at age 18, the youngsters completed a 28-item survey measuring their political attitudes on a liberal-to-conservative scale.

“Parents who endorsed more authoritarian parenting attitudes when their children were one month old were more likely to have children who were conservative in their ideologies at age 18,” the researchers report. “Parents who endorsed more egalitarian parenting attitudes were more likely to have children who were liberal.”

Temperament at age 4—which, of course, was very likely impacted by those parenting styles—was also associated with later ideological leanings.

“Individuals who were liberal at age 18 years were more likely than individuals who were conservative at 18 years to have had high levels of activity and restlessness at 54 months,” the researchers write. “The sense of restlessness may translate indirectly into a desire to challenge the status quo or to change social systems in desired ways.”

This is not to say that parenting styles are the only factor influencing a child’s evolving political attitudes. Many psychologists, such as Jonathan Haidt, argue that genes and the culture a child grows up in probably play a bigger role than parenting styles. Also, the Illinois researchers did not gauge the parents’ political beliefs.

Nevertheless, this new research provides solid evidence that—as was long suspected—children raised in households were discipline and obedience are emphasized are more likely to grow up holding conservative beliefs, and those raised in a more relaxed manner are more likely to become liberals.

Clearly, we pick up many of our assumptions about how the world works—and how it should work—at a very early age.