New research from Italy suggests the effect is independent of the ideology of one’s parents.

Given how strongly we tend to feel about our political beliefs, it’s somewhat disconcerting to think that they developed largely as a result of circumstances beyond our control.

Yet that’s the conclusion of a growing number of researchers, who have traced ideological predispositions to various personality traits and evolutionary needs. One idea, first raised in the 1990s, is that first-born children grow up to be more conservative, on average, than their siblings.

Newly published research from Italy confirms that thesis, and finds it is not related to the political beliefs of one’s parents. It suggests the first-born child is more likely to lean to the right regardless of his parents’ beliefs.

The sense of privilege that comes from being the subject of singular adoration sometimes steers one in a conservative direction.

“First-borns tend to favor the political and social status quo,” writes a research team led by Daniela Barni of the Catholic University of Milan. Its study is published in the journal Personality and Individual Differences.

The researchers looked at 96 Italian families, each of which consisted of a mother, father, and at least two children. Both parents and the first- and second-born children filled out a questionnaire designed to measure their level of agreement with conservative values.

They found that “birth order indeed fostered children’s conservatism directly.” However—contrary to earlier theories—they also noted that, “in our research, parents’ conservatism was not related to their offspring’s conservatism.”

“Children’s conservatism seems thus to depend on the dominance hierarchy in the sibling relationship,” the researchers conclude. While this dynamic can be explained by both Freudian and evolutionary theories, the simplest explanation is that the sense of privilege that comes from being the subject of singular adoration sometimes steers one in a conservative direction.

Barni and her colleagues are quick to note that a variety of influences create one’s ideological make-up; birth order is only one. But the dynamic is strong enough to have an impact on U.S. Supreme Court decisions, according to a fascinating 2012 study.

In any event, it’s intriguing to think that, if you and your sibling had switched places in birth order, you’d still be arguing about politics—only you might very well be taking the opposite positions.