My Teenager Is So Mean to His Little Sister—Is This Normal Sibling Behavior or Bullying?

As a psychologist working with families, I want to recognize that the "reason" for an older brother's mean treatment of his sister could be quite layered. Even without more details, however, you bring up a situation that rings true for many families and some general guidance may be helpful. First, sibling bullying is a thing, but often ignored as "normal sibling fighting" when it's not. Second, while our children still live in our homes with each other, we as the parents can have influence by taking steps to promote positive sibling relationships.

It's heartbreaking to watch people we love most in the world act like they hate each other. In your case, it's even harder to see a formerly close relationship change, while you probably also feel a sense of protection for your younger daughter. The challenge is to address what sounds like a power differential between your son and daughter, without making the problem worse by responding in a way that leaves him feeling like you're taking sides.

What Is a Typical Sibling Dynamic?

Adolescent development is all about identity development. This involves teenagers separating more from their families to figure out who they are as their own person. Consistent with the lore of parenting teenagers, this process often involves a fair amount of conflict, negotiation, and questioning rules and limits. When it comes to sibling relationships in adolescence, research has shown that adolescent siblings are more distant from each other than in elementary years. This is even more true with opposite-gender sibling pairs of cis-gender siblings. So, it may be normal for your son to not be as close to his sister. How he's acting, however, could be abnormal and qualify as bullying.

When Does It Qualify as Sibling Bullying?

Often overlooked as normal sibling fights, sibling bullying happens, and needs attention because it will not resolve on its own and can leave lasting damage. It sounds like the dynamic between your children might meet the definition depending on what you mean by "being hateful." The standard definition of sibling bullying includes the three following features: a power imbalance, repetitive behaviors, and intentional hurtful actions (e.g., name-calling, humiliation, intimidation). Note that these bullying behaviors do not need to be physically aggressive. One key consideration is that one sibling inflicts the hurtful behavior systematically toward the other, rather than an equal back-and-forth slinging.

Ways to Prevent Sibling Bullying

Parents may inadvertently contribute to the risk of sibling bullying. Here's what to avoid:

• Allowing siblings to "fight it out" when they do not have the problem-solving or conflict resolution skills to do so in fair ways. One study found that leaving siblings on their own to resolve arguments resulted in only 12 percent of sibling pairs doing so!
• Comparing siblings to each other.
• Using labels such as "the smart one" or "the athletic one." That can breed unhealthy comparison and jealousy.
• Showing favor for one child over the other.

Mediation Steps

In Melinda Wenner Moyer's recent parenting book rooted in tons of research studies, How to Raise Kids Who Aren't Assholes, she includes science-based tips for how to effectively lead mediation of sibling conflicts instead of letting them "figure it out." The four main steps include:

1. Establish ground rules that stop the fight as the issue gets worked out.
2. Allow each child a chance to describe what happened, and then identify common ground, as well as where there's disagreement.
3. Encourage discussing their feelings and repeating what the other said (promotes empathy and perspective-taking).
4. Help brainstorm solutions to practice conflict resolution.

How to Address Your Son

The above information is hopefully helpful to many families with different types of sibling conflict. Back to your family and what to do with your son. You are correct that you cannot force him to behave certain ways. Not knowing what you have already tried, the following suggestions depend on using your relationship for leverage to explore his behaviors to help motivate him to change.

The most common parenting response I see to similar scenarios is directing a child how they should behave differently ("you need to be nicer to your sister"). This often keeps families stuck because it does not uncover roots of the behavior, and as you probably know, children of all ages are not easily persuaded by "you should" or "you must." I encourage approaching the discussion with your son about his relationship with his sister with openness and curiosity, rather than direction, which likely feels like judgment to him.

Listen Instead of Lecture

You can even give yourself some ground rules to not tell him what to do (in this one conversation), framing your goal as understanding his experience of his sister and their relationship. This may reveal suprising pieces of information you would never had known, ultimately helping you address the problem more effectively. A few possible questions to get him talking:

"Tell me more about what makes it hard to get along with your sister."

"What do you think goes on between you two that I don't understand?"

"Any ideas what changed from when you used to be closer?"

The hope is that if he feels more understood, he feels safer exploring his own reasons for acting this way, and will be more receptive to changing his behavior. Another possibility is that something is going on with him that his sister has nothing to do with, but she is an easy target for his anger. This would also be important to understand so you aren't focusing all of your energy on promoting a positive sibling relationship, when that's not the actual culprit! If only teenagers were less complicated.

The Bottom Line

Watching your older son treat his younger sister poorly understandably brings out the protector in you, but also risks polarizing them further if he feels you treat her more favorably. I also want to be clear that gaining a better understanding of his experience does not equal sanctioning the behavior. What it can do is use the power of your relationship with him to help him change those behaviors. Realistically, this will not be a one-and-done interaction, but likely a series of discussions as he makes sense of himself and his actions in a way that helps him find his kinder, gentler brother self again.

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Emily Edlynn, Ph.D., is the author of The Art and Science of Mom parenting blog and the upcoming parenting book Parenting for Autonomy. She is a mother of three from Oak Park, Illinois and a clinical psychologist in private practice who specializes in working with children and adolescents.

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