Parents tend to favor daughters and conscientious children, new research finds

A new large-scale analysis sheds light on a question many siblings have asked at some point: “Who’s the favorite?” Published in Psychological Bulletin, the study found that parents are somewhat more likely to favor daughters, as well as children who are more conscientious or agreeable. Older siblings may also receive more freedom and autonomy. These subtle but consistent patterns of preferential treatment were drawn from a meta-analysis that included data from over 19,000 participants.

While a large body of research has documented the consequences of parental favoritism—showing that children who receive more favorable treatment often experience better mental health, stronger relationships, and higher academic achievement—relatively little is known about what drives this differential treatment in the first place. The researchers sought to move beyond the typical focus on how parenting affects children and instead examine how children’s own traits might influence the way they are parented.

This shift in perspective is grounded in the “child effects model,” a framework introduced by Robert Bell in 1968. The model challenges the traditional view of parenting as a one-way process from parent to child. Instead, it suggests that children actively shape their environments, including how their parents respond to them.

For example, a child who is calm, agreeable, and responsible may elicit warmer and more supportive parenting, whereas a child who is difficult or emotionally reactive may evoke more controlling or negative responses. Building on this idea, the researchers set out to explore whether specific child characteristics—such as gender, birth order, temperament, and personality—could predict which sibling is treated more favorably.

“80% of Americans have at least one sibling, and many of those who are only children have more than one child of their own,” said study author Alexander C. Jensen, an associate professor of human development at Brigham Young University. “In other words, this is such a common thing. Nearly all of us have experienced or will experience favoritism in families. So, I wanted to know who really does tend to be favored. As a bonus, I’m the youngest, so, are younger children really favored?”

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The researchers conducted a meta-analysis—a statistical technique that combines the findings of many separate studies to identify overall trends. Meta-analyses are especially useful when individual studies show mixed results or use different methods. In this case, the researchers analyzed 2,170 effect sizes from 87 sources drawn from 36 independent samples, representing 19,469 participants.

All studies compared how parents treated siblings within the same family. The included studies came mostly from the United States and Western Europe and varied widely in terms of the age of participants (from early childhood to late adulthood), who reported on the favoritism (parents or children), and what aspects of parenting were measured (such as affection, control, or resources).

To assess favoritism, some studies relied on perceptions—asking parents or children to rate how differently siblings were treated—while others used a “difference score” method, which compared reports about multiple siblings to identify disparities. These approaches allowed the researchers to analyze patterns across many kinds of parenting and reporting styles.

One of the clearest findings from the analysis was that conscientious children—those who tend to be responsible, organized, and self-disciplined—were slightly more likely to receive favored treatment. This was particularly evident when examining interactions that involved either more affection or fewer negative exchanges. Parents appeared to be more affectionate and less critical toward children who were seen as more conscientious.

Agreeable children were also more likely to be favored, though the effect was smaller. These children may be more compliant, cooperative, and eager to please, which could make parenting interactions smoother. However, this advantage did not extend to all domains of parenting. For example, agreeable children were not more likely to receive additional resources or money than their siblings.

“Children who are easier to parent are likely favored,” Jensen told PsyPost. “In our results, this was specifically children who were more responsible and compliant with parents.”

The analysis also explored personality traits that researchers thought might predict less favorable treatment—such as high levels of neuroticism, extraversion, or openness to experience—but found no consistent patterns. Similarly, there was no overall link between temperament and favoritism, despite earlier research suggesting that more emotionally reactive children might evoke harsher parenting. The authors suggested that the wide range of definitions and measurements for temperament across studies may have obscured meaningful effects.

Gender also played a role in parental favoritism. When looking only at parent-reported data, the researchers found that both mothers and fathers tended to report slightly more favorable treatment of daughters compared to sons. This pattern held across multiple countries, but it was somewhat more pronounced in the United States. Interestingly, when children themselves reported on favoritism, no gender differences were observed. In other words, parents may feel they favor daughters, but children may not perceive or interpret those differences the same way.

“Parents tend to favor daughters, but that is according to the perspective of parents – both mothers and fathers,” Jensen explained. “Children didn’t think gender was connected to favoritism. The gender findings were surprising. We expected mothers to favor daughters, but for fathers to favor sons. So, we were surprised that fathers favored daughters too.”

Birth order showed a more nuanced pattern. While the overall data suggested a slight preference for younger siblings, this effect disappeared once other factors were considered. However, older siblings were more likely to be granted autonomy and less likely to be tightly controlled by parents. These differences may reflect age-appropriate parenting—older children generally have more responsibilities and independence—but they can still be perceived as favoritism by younger siblings, especially if they feel the treatment is unfair.

The researchers also explored whether these patterns changed depending on the gender of the parent, the age of the children, or how favoritism was measured. Some of these factors made a difference. For example, favoritism toward older siblings was more apparent when both parents’ behaviors were considered together, and when the parenting domain involved control. However, the way favoritism was measured—whether by perception or score-based comparisons—did not seem to significantly change the results.

Like any study, this one had limitations. Although it drew on a large number of participants, the data came primarily from Western countries, so the findings may not generalize to other cultures where family roles and parenting norms differ.

“The data only represented North America and Western Europe,” Jensen noted. “Would we find different patterns in other parts of the world? Probably.”

The included studies also varied in how they defined and measured personality traits and temperament, which may have limited the ability to detect certain effects. Finally, even with a sample of nearly 20,000 people, the study is essentially a large collection of smaller, non-representative samples, rather than a reflection of the population at large.

“With a meta-analysis it is normal to have very large sample sizes,” Jensen said. “Our data represented over 19,000 people. With that, sometimes people think that the data must be representative and about as good as it gets. But that isn’t the case. Those 19,000 people were each part of smaller studies that were not representative themselves. So in many ways, this study is like a very large convenience sample.”

Still, the findings offer important insights into how parents interact differently with their children—and why. Jensen hopes this work can help parents and clinicians recognize when patterns of favoritism are emerging and reflect on how these patterns might shape children’s development. “All parents treat their children differently,” he noted, “but when those differences become unfair or more extreme, they can be problematic. I hope parents will take this study and be more reflective of which of their children they may tend to prefer.”

The study, “Parents Favor Daughters: A Meta-Analysis of Gender and Other Predictors of Parental Differential Treatment,” was authored by Alexander C. Jensen and McKell A. Jorgensen-Wells.