You’re on the phone with your mother, talking about your day while your two kids play in the living room. “Emma is doing great in school—she’s such a natural student. But I’m really worried about Jacob. He’s just not as academically inclined as his sister. I don’t know where he gets it from.” You speak casually, not realizing that Jacob has stopped playing and is now listening intently to every word, his small face processing the message that he doesn’t measure up to his sister.
Or maybe you’re at a family gathering, and relatives are asking about your children. “Sophie is our easy one—she’s always been such a sweet, cooperative child. But Max? He’s our handful. Always has been, always will be, I think.” You laugh as you say it, thinking you’re just making conversation and that Max is too busy with his cousins to hear. But later that night, Max asks you in a small voice, “Am I really bad, Mommy? Am I the bad one?”
Perhaps it’s a seemingly innocent moment during homework time. Your older daughter is struggling with math, and in frustration, you blurt out: “I don’t understand why this is so hard for you. Your brother got this concept immediately when he was your age.” The comment seems harmless in the moment—just an observation about different learning styles. But your daughter hears something else entirely: she’s not as smart as her brother, and you’re disappointed in her for not being like him.
These moments happen in families every day. We make casual comments, share observations with other adults, or attempt to motivate our children through comparison without fully realizing the profound and lasting impact our words have on sibling relationships and individual self-esteem. We tell ourselves we’re just being honest, just venting to trusted people, or just trying to help our children improve. But research tells a different story about how these seemingly innocent comments shape family dynamics for years—sometimes decades—to come.
The words we use to describe and compare our children don’t just vanish into the air. They become part of the family narrative, shaping how siblings see themselves, how they see each other, and whether they’ll maintain close relationships into adulthood. The sibling relationship is likely to last longer than any other relationship in one’s lifetime and plays an integral part in the lives of families. What we say about our children’s relationships with each other has the power to either nurture these lifelong bonds or drive wedges between siblings that may never fully heal.
The Research on Comparison, Favoritism, and Sibling Relationships
Understanding the science behind why certain statements are so damaging can help us appreciate why being mindful of our language matters so much. The research on sibling dynamics, parental favoritism, and family communication reveals patterns that every parent should understand.
Studies have found that most parents exhibit preferential treatment toward one child from time to time, but 40 percent of Americans raised with siblings believe their parents had a favorite child. This statistic is sobering because it reveals that even when parents think they’re being subtle or balanced, children are remarkably perceptive about differential treatment and favoritism.
What’s particularly concerning is how this perception persists. Studies show that up to 40% of people felt lonely growing up in families where favoritism existed. Whether intentional or not, favoritism can shape childhood relationships, self-esteem, and even adult mental health. The impact isn’t limited to childhood—it echoes through entire lives, affecting everything from career choices to romantic relationships to overall life satisfaction.
The research on how favoritism affects different children is nuanced and important for parents to understand. A recent BYU study unpacks this age-old sibling question and finds there’s often some truth behind the joke. Researchers discovered that younger siblings tend to get more parental warmth, while older siblings enjoy more independence. However, a study shows if a younger sibling feels like they’re the favorite and their parents agree, their relationship is strengthened. With older siblings, whether they feel favored or not, it has no major effect on the relationship. This suggests that birth order interacts with favoritism in complex ways that parents need to be aware of when considering how their comments might land differently with each child.
Theories of equity suggest that parental favoritism reduces the quality of sibling relationships, regardless of which children in the family are favored. This is a crucial finding: even the “favorite” child suffers when favoritism is present. The favored child often experiences guilt, anxiety about maintaining their position, or resentment from siblings that damages what could have been close, supportive relationships.
Recent research provides even more specific insights into how parental behavior affects sibling dynamics. A study investigating conditional regard found that it relates to sibling competition, favoritism, and conflict in teenage sibling dyads. Actor-Partner Interdependence Mediation Models showed that conditional regard was associated with lower sibling relationship quality. When children feel that parental love and approval are conditional on their performance or behavior—especially in comparison to siblings—it directly undermines the quality of sibling relationships.
Perhaps most importantly, research found that there is a contribution from parental attitudes, favoritism, and children’s age gap which can trigger sibling rivalry, with all variables having a significant sign. This confirms that parental language and attitudes aren’t neutral observations—they actively create and intensify sibling rivalry, or they can help prevent it.
The good news from research is that parents have tremendous power to shape positive sibling relationships. Adler argued that social comparisons and power dynamics in families, in particular sibling rivalry for family resources, were fundamental influences on personality development. He suggested that, as a means of reducing competition, siblings differentiate or de-identify, developing different interests and personalities. Understanding this dynamic helps us see that when we make comparisons, we’re not just describing differences—we’re actively pushing children to either compete more intensely or to give up entirely on areas where they feel they can’t compete with their siblings.
Understanding Birth Order Myths and Stereotypes
Before diving into the specific statements to avoid, it’s crucial to address the pervasive myths about birth order that often influence how parents talk about their children. Many of the most damaging comments come from internalized beliefs about what first-borns, middle children, or youngest children are “supposed” to be like.
The research on birth order and personality is clear and definitive: most of what we believe about birth order effects is myth. Despite a consistent stream of research, results remained inconclusive and controversial. In the last year, two definitive papers have emerged to show that birth order has little or no substantive effect on personality.
Large-scale research used data from three large national panels from the United States (n = 5,240), Great Britain (n = 4,489), and Germany (n = 10,457) to resolve this open research question about birth order effects on personality. The conclusion was clear: birth order doesn’t determine personality traits in the ways popular psychology suggests.
A 2024 study examining personality differences between birth order categories and across sibship sizes found that previous studies have generally found no associations except that firstborns average slightly higher than later-borns in intellect-related traits. Even this small difference is likely explained by environmental factors—firstborns often receive more one-on-one time and verbal interaction during early developmental years—rather than any inherent characteristic of being born first.
This research matters because it reveals how much of what parents say about birth order differences is based on stereotype rather than reality. When we label our firstborn as “bossy and responsible,” our middle child as “the peacemaker,” or our youngest as “the baby who can’t do anything alone,” we’re imposing culturally inherited narratives onto our children rather than seeing them as the unique individuals they actually are.
The Five Statements That Damage Sibling Relationships
1. “Why Can’t You Be More Like Your Sister/Brother?”
This statement is perhaps the single most damaging comparison a parent can make, yet it appears in countless family conversations—sometimes word-for-word, sometimes in subtler variations like “Your brother never had trouble with this” or “Your sister was doing this by herself at your age.”
Research from Utah State University’s national expert on siblings advises parents to avoid directly comparing children, such as “Why can’t you be more like your brother/sister?” Comparisons can promote anger, jealousy and resentment. This isn’t just an opinion about what’s polite—it’s based on decades of research showing that direct comparisons create lasting damage to both self-esteem and sibling relationships.
The child being compared unfavorably internalizes the message that they’re fundamentally not good enough as they are. They learn that their value is contingent on measuring up to someone else’s standard rather than being appreciated for their unique qualities. This can create lifelong struggles with self-worth, perfectionism, and the feeling that they’ll never be quite enough.
The child who’s held up as the positive example doesn’t escape unscathed either. They may develop anxiety about maintaining their “superior” position, guilt about being favored over their sibling, or pressure to always perform at high levels. They may also face resentment and hostility from siblings who’ve been told they’re not as good, damaging what could have been close, supportive relationships.
These comparisons teach children that love and approval are earned through competition with siblings rather than given freely. They create family cultures where siblings see each other as rivals for parental affection rather than natural allies and supporters. Research shows that siblings who receive favored parental treatment tend to have better mental health, fewer problem behaviors, and more academic success. But this comes at the cost of siblings who don’t receive favoritism, who experience worse outcomes and often lifelong resentment toward both parents and siblings.
What makes this particularly insidious is that parents often make these comparisons with good intentions. They believe they’re motivating the struggling child or providing a concrete example of desired behavior. But children don’t process these statements as helpful guidance—they process them as evidence that their sibling is better and more loved than they are.
Even seemingly positive comparisons create problems. “You’re so much better at math than your brother” sounds like praise, but it still positions siblings in competition and creates pressure to maintain superior performance. It also implies that the child’s value lies in being better than someone else rather than in their own inherent worth.
2. “She’s the Smart One, He’s the Athletic One” (Or Any Other Labels)
Labeling children with specific roles or characteristics—especially when those labels differentiate them from their siblings—creates rigid identities that can limit children’s development and poison sibling relationships.
Research specifically advises avoiding labeling, such as “the funny one,” “the smart one” or “the quiet one.” Highlighting each child’s unique strengths without creating exclusive categories is crucial. When we assign these labels, we’re not just describing our children—we’re creating self-fulfilling prophecies that can limit their potential and damage their relationships with each other.
Labels create several harmful dynamics. First, they restrict children’s sense of possibility about who they can become. The child labeled “the athlete” may feel pressure to continue excelling in sports even if their interests shift, or they may feel they can’t also be “smart” because that’s their sibling’s role. The child labeled “the smart one” might avoid physical activities because they’ve learned that isn’t their domain, missing opportunities for development and enjoyment.
Second, labels create artificial scarcity—the sense that there’s only room for one child to occupy each positive role in the family. If one sibling is “the artist,” another child who loves art may feel like they’re encroaching on their sibling’s territory or competing for a role that’s already been assigned. This prevents children from exploring their full range of interests and abilities.
Third, labels often carry implicit value judgments that create hierarchies between siblings. In our culture, being labeled “the smart one” typically carries more value than being “the social one,” and being “the responsible one” is generally praised more than being “the fun one.” Children pick up on these hierarchies, learning that some siblings are inherently more valuable or important than others.
Research shows that these labels become part of children’s identity in ways that persist into adulthood. Adults who were labeled in childhood often struggle to see themselves outside these assigned roles, even decades later. “I was always the difficult one in my family” or “I was never as smart as my sister” are statements that reveal how childhood labels become internalized as permanent truth.
The most pernicious aspect of labeling is that it often contains a grain of truth—one child might currently show more interest in academics while another prefers sports—but by naming and reinforcing these differences, parents make temporary preferences into fixed identities. Children are constantly developing and changing, and labels prevent them from evolving beyond the roles assigned to them in early childhood.
3. “I Love You Both the Same”
This statement might seem like it belongs on a list of things parents should say rather than things to avoid, but research and clinical experience reveal that this seemingly reassuring phrase often causes more harm than good—especially when said in front of siblings or in response to questions about favoritism.
The problem with “I love you both the same” is that it’s not what children are actually asking for or needing to hear. Love isn’t a finite resource that must be divided equally like slices of pie. When children express concerns about fairness or favoritism, they’re usually seeking assurance about something specific—whether you understand their unique needs, whether you value their particular qualities, or whether you’ll be there for them individually.
Declaring that you love all children identically actually dismisses their individuality. It suggests that the appropriate parental response is to feel and express identical emotions toward very different people, which children instinctively recognize as impossible or dishonest. Real love involves responding to each person’s unique qualities, needs, and personalities—not treating everyone identically.
This statement also often comes across as defensive rather than reassuring. When a child asks “Do you love her more than me?” and receives “I love you both the same,” they often hear a parent who’s uncomfortable with the question rather than one who’s genuinely addressing their concern. Children need parents to be able to sit with these difficult questions rather than brushing them aside with blanket statements.
What children actually need to hear is that they’re uniquely valued as individuals. “I love you for exactly who you are” speaks to their specific worth rather than making them part of an undifferentiated group. “I love your creativity and the way you solve problems” acknowledges their unique qualities rather than lumping them together with siblings.
Additionally, “I love you both the same” often precedes or follows moments of obvious differential treatment, making it ring hollow. If you’ve just spent an hour at one child’s soccer game but only fifteen minutes at another’s art show, then declaring equal love doesn’t address the real concern—which is about time, attention, and demonstrated priority, not about emotional capacity.
4. “He’s Just Like That—We’ve Learned to Live With It”
This statement and its variations—”She’s always been difficult,” “He’s my challenging one,” “She’s just high-maintenance”—are often shared between parents, with other adults, or even said directly about children in their presence. They’re particularly damaging because they present personality characteristics or behavioral patterns as fixed, unchangeable aspects of a child’s identity, often in explicit or implicit comparison to easier or more compliant siblings.
These statements communicate several harmful messages. First, they tell the child that their fundamental nature is problematic and that the family has resigned itself to tolerating them rather than genuinely accepting and celebrating them. No child should grow up feeling like they’re something their family has “learned to live with.”
Second, these statements suggest that change isn’t possible—that the child is inherently difficult or challenging rather than someone who’s going through a difficult phase, struggling with something specific, or still developing emotional regulation skills. This robs children of hope that they can grow and develop, and it often becomes a self-fulfilling prophecy as children live up (or down) to these lowered expectations.
Third, when said in comparison to siblings (explicitly or implicitly), these statements create both resentment and guilt. The “difficult” child resents being positioned as the family problem while their sibling is seen as easy and pleasant. The “easy” child may feel guilty about receiving more positive attention and may develop anxiety about maintaining their favored position.
Research on sibling relationships reveals that parents often contribute to differentiation between siblings through the language they use. When we consistently describe one child as difficult and another as easy, we’re not just observing differences—we’re actively creating and reinforcing them. Children internalize these labels and often become more extreme versions of what we describe.
What’s particularly troubling is that these statements are often shared casually in the child’s hearing—on phone conversations, at family gatherings, or in discussions with partners—as though children aren’t absorbing every word. Children who overhear themselves described as problems, challenges, or difficulties to be endured develop deep shame about their fundamental nature.
The long-term impact of these labels is significant. Adults who were labeled as “difficult” or “challenging” children often struggle with shame, relationship difficulties, and beliefs that they’re inherently problematic. They may approach new relationships expecting to be too much for people, or they may develop defensive patterns to protect themselves from anticipated rejection.
5. “Don’t Tell Your Brother/Sister About This” (Creating Secrets and Inequity)
This statement represents a broader pattern of creating differential treatment through secrets, special privileges, or hidden inequities. While it might seem like a way to avoid conflict or give each child individual attention, research and clinical experience show that secrets between parents and one child that exclude siblings create lasting damage to trust and sibling relationships.
Children have remarkably sophisticated fairness detectors. Even when parents believe they’re successfully hiding differential treatment, children typically know—or at least sense—when their siblings are receiving special treatment, gifts, or privileges that they’re not. The secrecy often creates more damage than the inequity itself because it teaches children that honesty and transparency aren’t values their parents actually prioritize.
Secrets also create unhealthy dynamics where children are positioned as confidants or special allies with parents in ways that exclude siblings. This can feel good to the included child in the moment, but it ultimately damages sibling relationships by creating insider/outsider dynamics. The child who’s brought into the secret may feel special but also burdened by the need to hide things from siblings. The excluded children, when they inevitably discover the secret, feel betrayed by both the parent and the sibling who participated in the deception.
There are certainly times when age-appropriate differences in privileges, information, or treatment are necessary and healthy. Teenagers need different privacy, autonomy, and information than young children. What’s damaging isn’t differential treatment based on developmental needs—it’s secretive differential treatment based on favoritism or arbitrary decision-making.
The healthy approach to necessary differences in treatment is transparency and explanation. “Your brother gets to stay up later because he’s older, and when you’re his age, you’ll have the same bedtime” is honest and gives the younger child something to look forward to. “Don’t tell your brother, but you can stay up late tonight” creates resentment and teaches children that favoritism should be hidden rather than addressed.
Secrets also prevent children from processing their feelings about differential treatment. When inequity is acknowledged openly, children can express their disappointment or frustration, and parents can validate those feelings while explaining their reasoning. When inequity is hidden, children are left to process confusing feelings of suspicion and exclusion without being able to talk about what’s happening.
The Long-Term Impact on Adult Sibling Relationships
The statements we make about and between our children during their formative years have profound effects that extend far beyond childhood. Research on adult sibling relationships reveals patterns that trace directly back to parental language and treatment during childhood.
Adults who grew up in families where parents openly compared siblings or showed clear favoritism often report strained or distant relationships with siblings in adulthood—or no relationship at all. The childhood competition for parental approval and the resentment created by differential treatment can persist for decades, preventing siblings from ever developing the close, supportive relationships they might have had.
Even when adult siblings maintain contact, the patterns established in childhood often continue to play out. The sibling who was consistently positioned as more successful may feel obligated to help the sibling who was positioned as less competent, creating resentment on both sides. The sibling who was labeled as difficult may continue to be blamed for family problems, even in adulthood.
Perhaps most tragically, parents often don’t see the connection between their childhood statements and their adult children’s distant or hostile relationships with each other. They wonder why their children don’t spend holidays together or why there’s tension at family gatherings, not recognizing how their own comparisons, labels, and differential treatment created fractures that never fully healed.
The good news is that research also shows sibling relationships can be repaired in adulthood, often through open conversations about childhood experiences and acknowledgment of how parental treatment affected the relationship. But prevention is far easier than repair, and the statements parents avoid making in childhood can spare everyone years of pain and estrangement.
What To Say Instead: Building Positive Sibling Relationships
Understanding what not to say is only half the equation. Parents also need alternative language that honors each child’s individuality while fostering positive sibling relationships.
Instead of comparing siblings, describe each child’s specific qualities: “You have such creative ideas for solving problems” rather than “You’re better at this than your brother.” This acknowledges the child’s abilities without positioning them in competition with siblings.
Instead of labeling children with fixed roles, acknowledge their current interests and efforts: “You’ve been really enjoying basketball lately” rather than “You’re the athlete.” This leaves room for interests to evolve and for siblings to share domains.
Instead of declaring equal love, express unique love: “I love the way you think about things and how you care so much about animals and the way you make people laugh.” This specificity shows you see them as individuals rather than interchangeable family members.
Instead of describing a child as difficult, address specific behaviors or developmental stages: “You’re working on learning to manage big feelings right now, and that’s hard work” rather than “You’re my difficult one.” This frames challenges as temporary and changeable rather than permanent personality defects.
Instead of creating secrets, be transparent about necessary differences: “Your sister gets different privileges because she’s older. When you’re that age, you’ll have those same opportunities” rather than “Don’t tell your sister.” This teaches fairness, patience, and the relationship between age and responsibility.
Focus on fostering sibling connection rather than comparison. Celebrate when siblings support each other: “I loved seeing you cheer for your brother at his game.” Encourage collaboration: “You two work together so well when you build things.” Point out their positive relationship: “You and your sister have such a special bond.”
Moving Forward With Awareness and Intention
Becoming aware of how our language affects sibling relationships can feel overwhelming, especially if you recognize patterns you’ve already established. Remember that awareness is the first step toward change, and it’s never too late to adjust how you talk about and to your children.
If you recognize that you’ve made damaging statements in the past, consider having honest conversations with your children—age-appropriately—about what you’ve learned. “I’ve realized that sometimes I’ve compared you to your sister, and I understand now that probably didn’t feel good. I’m working on appreciating each of you for who you are individually.” This models accountability and growth rather than perfection.
Pay attention to how you talk about your children to other adults, especially in situations where your children might overhear. The casual conversations we have with partners, friends, or extended family often reveal our unconscious beliefs about our children and create lasting impressions—both for the children themselves and for how others in their lives perceive them.
Notice patterns in your language. Do you consistently describe one child in more positive terms than another? Do you frequently compare siblings’ behaviors or abilities? Do you label children with fixed characteristics? Awareness of these patterns is essential for change.
Remember that your goal isn’t to avoid ever noticing or acknowledging differences between your children. Children are unique individuals with different personalities, strengths, challenges, and interests. The goal is to acknowledge and celebrate these differences in ways that don’t create competition, hierarchy, or resentment between siblings.
Your children’s relationships with each other are among the most important relationships they’ll have in their entire lives. The words you use to describe and compare them play a powerful role in shaping whether those relationships are characterized by competition and resentment or by support and genuine affection. Choose your words with the care these lifelong relationships deserve.
What patterns have you noticed in your own language about siblings? Have you found effective ways to celebrate each child’s uniqueness without creating comparison or competition? Share your experiences in the comments—your insights might help another parent build stronger sibling bonds in their family.