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

CBC

29-01-2025

This may not feel like news if you have siblings and a long-standing hunch that one of you could rob a bank and still be the golden child.
But a new study suggests parents really do have a favourite kid based on birth order, gender and personality. Although the reasons may be more complex.
Younger siblings generally receive slightly more favourable treatment from their parents, according to 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in 30 different studies published in the U.S., Canada and Western Europe between 2015 and 2022, plus an additional 14 unpublished databases.
However, this favouritism for the baby of the family was no longer true when the authors looked specifically at control and autonomy as predictors, and then, parents preferred the eldest. In other words, parents were less controlling of older siblings.
Parents also reported slightly favouring daughters over sons. But personality played a role, too, with the authors noting that parents tended to favour children who were "agreeable" and "conscientious," regardless of birth order and gender.
"Our findings specifically suggest that within families, some children may be easier to parent than others," the authors wrote in the study, which was was published in the American Psychological Association's Psychological Bulletin earlier this month.
The researchers from Brigham Young University (BYU) in Provo, Utah, and Western University in London, Ont., looked at birth order, gender, temperament and personality and whether these predicted parental differential treatment. The authors analyzed responses from parents and siblings.
The study has been making headlines around the world. But Lisa Strohschein, a sociology professor at the University of Alberta and the editor-in-chief of the journal Canadian Studies in Population, suggests this may be because the story simply fits narratives people already have about parental preferential treatment.
The study itself had very small effect sizes, she cautioned, to the point that they're nearly "trivial." Even the authors acknowledge their small effect sizes in their limitations, Strohschein added, where they write that "the reasons why parents treat their children differently are likely more complex and extend beyond the factors explored in this study."
"If parents are preferring one child over another, that can have really toxic effects," Strohschein, who was not involved with the new study, told CBC News.
"It's very common, but I don't think it depends on age or gender or birth order as much as we think."
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Favouritism is common
The prodigal son. The golden child. The rebel. As much as parents may deny it, the belief that parents prefer one sibling over another is entrenched throughout our culture.
For good reason. A swath of research suggests parental favouritism is quite common, occurring in as many as 65 per cent of U.S. families. In studies, it's called "parental differential treatment," or PDT for short. It's been reported across other countries, like China and Mexico, and has been associated with children's psychosocial well-being.
2020 study in Hong Kong.
And other studies that examine the predictors of PDT, like birth order and gender, have shown similar results. For instance, a 2003 study suggested parents often favour the youngest child. A 2006 study said mothers often favour daughters over their sons.
"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," BYU School of Family Life professor Alex Jensen said in a news release.
"Watch for those patterns within yourself. Pay attention to how your children react to things that could be perceived as favouritism."
But Strohschein stresses that parenting isn't fixed; it's dynamic, changing over time as children get older and parents get more experienced. So she says that asking flat questions in studies like these, like "did your parents favour girls over boys," doesn't necessarily reflect the reality of who parents are and how they treat their children.
"You're learning as you're going," Strohschein said.
Good news for middle kids?
But as for the current study's finding that parents tended to favour the more agreeable and conscientious child? That may be good news for middle children, according to new Canadian-led research published at the end of December in the journal Proceedings of the National Academy of Sciences
That study of more than 700,000 online participants from Canada, the U.S., Australia and the United Kingdom found that middle children were more co-operative.
That's in contrast to most previous research, which had found that adults' personality trait levels were unrelated to their birth order, Michael Ashton, a psychology professor at Brock University, and lead author of the Canadian study, told CBC News. But his research found that middle-borns scored highest on two personality dimensions involving co-operativeness —specifically, honesty/humility and agreeableness.
That said, he noted that the findings may relate more to family size than birth order, since middle children tend to be from larger families. And on average, people from larger families tended to be higher in these co-operative traits.
"We suspect that when one grows up around siblings, even during one's first few years, there's a greater need to co-operate, which leads one to develop a slightly more co-operative personality," Ashton said.
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