As Philip Larkin once pointed out, your parents have a lasting influence on you. Now, researchers have revealed which siblings in the family are more likely to be favored: And that's bad news for sons.

The researchers found that daughters, older children, and those who were more conscientious or more agreeable were likely to receive preferential treatment.

The study's authors said the findings have important implications, adding that previous research has shown that differential treatment of siblings can have negative effects on children's development, particularly for those who are less popular.

"Parents and clinicians should understand which children in a family tend to be favored as a way to identify potentially destructive family patterns. ” they wrote.

Article published in Psychological Bulletin, Alexander Jensen and McKell Jorgensen-Wells, Brigham Young University, USA, and Western University, Canada, respectively, report how they analyzed data from multiple sources, including 30 peer-reviewed journal articles, covering 19,469 diverse participants from the United States and Western Europe and Canada.

The pair considered siblings' birth order, their self-reported gender, temperament and personality, and explored whether these were associated with aspects of parental preference.

In most cases, sources used only children's reports of parental favoritism, although some cases also included parents' reports.

When the researchers considered whether the data came from peer-reviewed sources, they found that older siblings tended to be favored by their parents, at least in areas of control, and that such offspring tended to be given greater autonomy, and Will be favored by parents. Less controlling than their younger siblings.

They noted that this difference could have important consequences.

"One challenge for parents is that differential control, whether developmentally appropriate or not, is associated with lower self-worth and more problem behaviors in unfavored siblings during childhood and adolescence," they wrote.

Additionally, parents reported a preference for daughters, although the children did not notice this—which the authors noted may indicate that, on average, girls are easier to parent.

The findings also showed that conscientious children were more likely to be favored by their parents, while more agreeable children were slightly less prejudiced.

However, the study had limitations, particularly the team's inability to account for the role of perceived fairness in parenting differences.

Additionally, further research is needed to investigate whether the proposed patterns are the same across different life stages.

The researchers added that the effect size was small, noting that "the reasons why parents treat their children differently may be more complex and beyond the factors explored in this study."

Laurie Kramer, a professor of applied psychology at Northeastern University in Boston, cautions that the data were collected in different ways from different sources, and the analysis did not take into account potential changes in cultural norms over the decades.

But, she added, an important finding is that the characteristics and behaviors of the children themselves may influence parents' attitudes.

"The idea that children can make it more or less easier for their parents to raise them is really important," she said, although she noted that further research should explore whether parental preferences also influence children's temperaments.

Carl Pillemer, a professor of human development at Cornell University, said the findings are illuminating, but noted that different children may be favored for different things.

"Parents do differentiate between their children, but that doesn't necessarily mean they like or love one child more than another," he said.

Pillemer added that his own research has found that parents work hard not to act out or act according to their preferences.

"Problems arise when children's almost universal sense of preference translates into treating them differently," he says. "We can't control how we feel, but we can definitely help how we treat our children."