Every family jokes about who the “favourite child” might be, but new research suggests those jokes may hold a grain of truth.

A study titled “Parents Favor Daughters: A Meta-Analysis of Gender and Other Predictors of Parental Differential Treatment”, published in Psychological Bulletin, combined results from dozens of earlier studies to see how parents treat their children differently. This method, called a meta-analysis, pulls together data from many sources to identify consistent patterns across a large number of families.

Led by Professor Alexander C Jensen of the School of Family Life at Brigham Young University in Provo, Utah, the research team reviewed information from 30 published studies and 14 additional data sets, representing more than 19 000 people. They found that parents were more likely to favour daughters and that children described as agreeable and conscientious often received more positive attention. Younger siblings tended to experience more parental warmth, while older ones were usually granted more freedom and responsibility.

Professor Jensen said these patterns are not necessarily a sign of unfairness but of normal family dynamics that parents can learn to manage. “It is helpful to take the findings from this study and be aware of the patterns that could be happening in your family,” he explained. “When parents are aware, they can make small adjustments that benefit everyone.”

He added that most parents: “probably connect more easily with one child over another, whether that be due to personality, birth order, gender or other things like shared interests,” and encouraged them to: “watch for those patterns within yourself” and notice: “how your children react to things that could be perceived as favouritism.”

The study also found that feeling less favoured can lead to tension between siblings or hurt a child’s confidence. Jensen advises that small efforts such as explaining different rules or recognising each child’s strengths can go a long way toward creating a fair and loving home.