Yes, your parents may have treated you differently; here’s how it shaped your mental health
By Dolores Tropiano, ASU News
April 9, 2026

If you’ve ever felt that your parents treated your siblings differently than they treated you, you may be right.

According to Arizona State University researchers, differences in how parents treat their children are more common than many realize.

But before placing all the blame on parents, there’s more to the story. Children may also play a role in shaping how they are treated. 

While parents often strive to provide the same amount of attention and affection to all their children, a range of factors can make that difficult. Achieving perfectly equal treatment is not always easy.

Kathryn Lemery-Chalfant, a professor in ASU’s Department of Psychology, and doctoral student Janna P. Maravilla looked at data drawn from the Wisconsin Twin Project, a major 30-year longitudinal twin study that Lemery-Chalfant co-directed.

Pulling information about 632 pairs of twins — from infancy to early adulthood — and their parents, they examined how parents treated each child, how children perceived favoritism and how those differences shaped each child’s behavior and mental health in important ways.

The study1 was funded by the National Institute of Mental Health and has been accepted into the journal Development and Psychopathology.


In recognition of National Sibling Day on April 10, Lemery-Chalfant talks about the roles both parents and children play when it comes to preferential treatment and provides tips to guide parents who are raising multiple children. 

Note: Answers have been edited for length and/or clarity.

Question: Your study suggests what many children have long suspected — that parents don’t treat siblings the same. How common is this, really?

Answer: There are real differences in how parents treat their different children and on top of that, there are perceived differences. Parents report some partiality and children report a lot more. 

Both real and perceived differences are important for children’s mental health. If you feel like your parents love your sibling more than they love you, that can have a big impact on your development. This is probably because these differences activate the attachment system. 

Your relationship with your parents is fundamental for forming relationships throughout your life. If you feel less loved than your sibling, it can lead to lower self esteem, feelings of rejection and increases in anxiety and depression. The less favored child may overcompensate, act out or withdraw. They may be more insecure in future relationships, for example, constantly comparing how they are treated by their romantic partner to how others are treated. 

Q: What’s the biggest misconception people have about favoritism between siblings?

A: Parents might feel like it is no big deal — siblings won’t notice if one of them receives more warmth, attention and less punishment than others. But, because of the attachment system, children are hypersensitive to any differences in parental treatment. 

Q: How does being treated differently by parents affect a child’s mental health? Are certain types of differential treatment more strongly linked to behavioral issues?

A: In our study, we found that children were particularly sensitive to differences in discipline. Differences in discipline were related to all types of mental health problems in children. In addition, differences in fathers’ affection and preference for one sibling over another was associated with anxiety and depression.  

Q: One of the significant findings in your study suggests that children’s behavior can shape how parents treat them. Does this mean parents aren’t necessarily “causing” these differences, but sometimes reacting to them?

A: In this study, children’s inattentive and acting out behaviors elicited more intrusive and hostile parenting. The negative parenting was a response to the children’s behaviors. This is an important finding because society can blame parents for their children’s mental health problems and assume that negative parenting causes children’s poor behavior. Instead, interventions can make parents aware that children’s negative behavior can lead to poor-quality parenting and coach parents on how to set boundaries and be consistent with children showing negative behavior.

Q: What other factors contribute to one child being treated differently from another?

A: Parental differential treatment can be in response to real differences in children and their needs. For example, children with physical and developmental disabilities may need more parental assistance in caretaking. Siblings are usually understanding about these real differences in needs. 

Beyond these real differences between siblings, parents may have biases that further contribute to differential treatment. For example, parents may feel that boys are naturally more active and aggressive than girls and thus should be allowed to be more physical and independent, with freedoms such as later curfews. 

Other biases may lead to differential treatment by birth order, physical attractiveness or personality. Siblings are less understanding of parental differential treatment due to biases. Together, real differences between siblings and parental biases lead to parental differential treatment. 

Q: What should parents take away from this? Is it realistic or even advisable for parents to treat siblings exactly the same?

A: Children should feel loved by their parents. One way to show all your children that they are loved is to treat them similarly. The best type of parenting out there is called authoritative parenting. Authoritative parents show a lot of love and warmth toward their children. They listen to their children and allow them to make decisions and argue a point. 

However, they also structure their children’s activities and set limits with them. Children of authoritative parents know what is expected of them and the consequences if they break the rules. With parental love and support, siblings are close to each other, they work hard and do well in school and they also form strong friendships and relationships with others outside of the home.

Q: If you could give parents one piece of advice about raising multiple children, what would it be?

A: There is no replacement for good communication. If you must treat your children differently — for example, you are planning on taking one of them on a trip but not the other — then sit down with the child that will be left behind and explain why. Reassure them that you love them and it will be their turn for a special event or outing in the future.  

Be aware of your own biases — are you treating your children differently because of their gender, personality or physical looks? Try to uniquely value each child and be fair with your attention. It is helpful to be intentional in spending one-on-one time with each child. 

Avoid comparing siblings to each other, and avoid labeling your children — for example, “the smart one” and “the athlete.” Labels are too simplistic and can easily lead to differential treatment. Instead, validate their unique strengths. 

Encourage sibling cooperation to reduce competition and rivalry. Work together to reach family goals and celebrate family accomplishments. 

Remember, most importantly, children need to feel loved. 

This story originally appeared on ASU News.

1 Other authors on the study include: Courtney Lyding, former undergraduate student, and ASU staff member Sierra Clifford.