Parents really do have a favourite child, new study suggests. And it’s probably who you think it is

Parents have long been suspected of having a favorite child, but a new study suggests that this favoritism may be based on birth order, gender, and personality traits. The study, which was a meta-analysis of nearly 19,500 people in 30 different studies published in the U.S., Canada, and Western Europe between 2015 and 2022, found that younger siblings generally receive slightly more favorable treatment from their parents. However, when looking specifically at control and autonomy as predictors, parents actually preferred the eldest child.

The study also found that parents reported slightly favoring daughters over sons, but personality traits played a significant role as well. Parents tended to favor children who were “agreeable” and “conscientious,” regardless of birth order and gender. The researchers from Brigham Young University and Western University looked at birth order, gender, temperament, and personality to predict parental differential treatment. While the study has made headlines around the world, some experts caution that the effect sizes are quite small and the reasons for parental favoritism are likely more complex than the study suggests.

Parental favoritism, also known as parental differential treatment (PDT), is quite common, occurring in as many as 65% of U.S. families. Studies have shown that PDT can have a significant impact on children’s psychosocial well-being, leading to feelings of competition or injustice among siblings. While some studies have suggested that parents often favor the youngest child or daughters over sons, experts emphasize that parenting is not fixed and can change over time as children grow older.

A recent Canadian-led study found that middle children may have an advantage when it comes to parental favoritism. The study of over 700,000 participants from Canada, the U.S., Australia, and the U.K. found that middle children tend to be more cooperative, scoring highest on personality dimensions involving co-operativeness. The researchers suggest that growing up around siblings, especially in larger families, may lead to the development of a more cooperative personality.

Overall, while parental favoritism may be a common phenomenon, experts stress that parenting is dynamic and can change over time. It’s important for parents to be aware of any potential favoritism and strive to treat each child fairly and equally. By paying attention to how their children react to different situations, parents can work to create a positive and supportive family environment for all of their children.