Playing favorites with twins can harm both children's mental health and their relationship with each other, but favoritism is often not a deliberate choice—it's how you respond to each child's different temperament and needs. Research shows that when twins perceive they receive less parental love or attention than their sibling, they develop higher rates of anxiety, ADHD, and behavioral problems that can persist into adulthood.
The distinction matters because equal treatment is not the same as fair treatment. Your twins are genetically identical or not, born with different personalities, and growing at different paces. The goal is not sameness but recognition—ensuring each child feels equally valued as a unique person, even when your actual time or attention differs based on their real needs.
Table of Contents
- What the Research Shows About Differential Treatment
- Identical Twins Versus Fraternal Twins—Why Genetics Matter
- The "Good Twin / Bad Twin" Trap and How Labeling Causes Estrangement
- How Much Is Parental Choice Versus Child Temperament?
- Spotting Real Favoritism Versus Normal Individual Attention
- Why Individualized Parenting Actually Strengthens Twin Bonds
- Practical Strategies to Protect Against Favoritism
- Repairing Favoritism That Has Already Happened
- How Needs and Fairness Change With Age
- When to Seek Professional Help
- Frequently Asked Questions
What the Research Shows About Differential Treatment
A large study of 632 twin pairs with an average age of 7.6 years measured how often parents treated one twin differently from the other through observed parent-child interactions and reports from mothers, fathers, and children themselves. Differential parental treatment was strongly associated with higher rates of anxiety, ADHD, and behavioral problems in both twins, according to researchers at Cambridge Core.
The effect was measurable but not absolute—some twins treated differently developed no symptoms, while others did. Importantly, the difference was not small: children who perceived receiving less parental love or attention than their twin developed significantly higher rates of anxiety, ADHD, and behavioral problems, with effects remaining measurable into adulthood, according to research from the University of Toronto.
The timing matters most during early childhood through elementary school, when twins are forming their sense of self in relation to their sibling. A six-year-old notices whether Mom spends more time helping the other twin with homework. A ten-year-old remembers whether Dad always attended one twin's soccer games but not the other's. These observations shape how they see themselves and their place in the family.
The research does not prove that all differential treatment causes harm—only that it is correlated with measurable symptoms. Some differences in how you parent each twin reflect responsive parenting, not favoritism. The key is whether the difference is visible to the twins and whether it sends the message that one child is more valued.
Identical Twins Versus Fraternal Twins—Why Genetics Matter
Parents naturally treat identical twins more similarly than fraternal twins, and this difference is not a choice. Identical twins share 100 percent of their DNA, while fraternal twins share about 50 percent, the same as non-twin siblings. Because identical twins are genetically more similar, parents respond to them more similarly in terms of how much attention and affection they distribute, according to University of Toronto research on twin parenting.
This creates a practical advantage: if your identical twins have similar needs, similar temperaments, and similar abilities, equal treatment is easier to achieve simply by accident. A parent might naturally spend the same amount of time with each because each child is easier to parent in the same way.
Fraternal twins, by contrast, may have very different activity levels, emotional needs, and interests from birth. One might be highly social and the other more reserved. One might excel at sports and the other at music. If you respond to those differences—spending more time at one child's soccer games because that child plays soccer, not because you favor that child—you are not playing favorites.
You are being responsive. The trick is distinguishing which differences are genetic and which are learned. A child who sees a sibling labeled as "the athlete" might suppress their own interest in sports to maintain a distinct identity. A child who learns the other twin is "the smart one" might stop trying in school. These identity patterns are learned, not inborn, and they are the most damaging form of favoritism.
The "Good Twin / Bad Twin" Trap and How Labeling Causes Estrangement
Assigning opposite identities to twins—one as the "good" twin and one as the "bad" twin, or one as the "smart" twin and one as the "athletic" twin—is one of the most damaging forms of favoritism. When parents engage in this kind of labeling, twins internalize opposite identities and struggle to maintain closeness with each other, often resulting in long-term estrangement, according to Psychology Today.
These labels are sticky. Once a twin is "the troublemaker," they have little incentive to behave differently—the label has already become their identity. The other twin, cast as "the responsible one," may feel burdened by always meeting expectations and resentful of the sibling who gets away with more. Both twins suffer. The damage extends beyond the moment the label is applied.
Twins who grow up in opposition to each other often lack the foundation for a close sibling relationship in adulthood. They have learned to define themselves against each other, not alongside each other. A thirty-year-old twin who spent childhood as the "difficult" twin may carry shame into every relationship with their sibling. Parents usually apply these labels unconsciously, reinforcing a pattern that started early.
"She was always the calm one" becomes a statement repeated so often that the calm twin stops trying anything new and the active twin feels judged for having energy. Neither label reflects the full truth of either child.
How Much Is Parental Choice Versus Child Temperament?
Here is where the guilt should stop: parental behavior is not purely a choice. Research on the heritability of child behaviors shows that approximately 34 percent of hostility in young girls and 51 percent of parental intrusiveness overall have genetic components—meaning children's own inborn traits partially elicit parental behavior, not the reverse.
This means a clingy child genuinely gets more attention because the child seeks it, not because the parent chose to give it. An easily frustrated child triggers more correction because the child's behavior requires response. A child with a naturally outgoing personality draws parents into more social activities. These are not favorites—they are responses. The responsibility, then, is not to treat each twin identically but to monitor whether your responses reinforce a harmful pattern.
If one twin's temperament makes them higher-maintenance, do you make a point to spend separate positive time with the other twin? If one twin seems to irritate you more, do you work on your response, or do you let frustration shape how you treat them? A parent with a naturally withdrawn twin should not be blamed for spending more time with the outgoing one. But they should notice the pattern and deliberately create separate time with the withdrawn child in settings where that child feels comfortable—quieter, one-on-one, without comparison.
Spotting Real Favoritism Versus Normal Individual Attention
Real favoritism looks like consistent preference for one twin's feelings, interests, or needs over the other's. A parent who always sides with one twin in conflicts, regardless of who is right. A parent who enrolls one twin in activities they enjoy and tells the other to "just wait in the car." A parent who praises one twin's artwork while being dismissive of the other's efforts.
Equal does not mean identical. Equal means each child receives recognition for who they are. One twin might join soccer and the other might join debate club, and that is fine—you are not playing favorites. But if the soccer twin gets a celebratory dinner after every game and the debate twin's tournament placements go unnoticed, you are playing favorites.
Warning signs include: one twin frequently complaining they get less of something (time, praise, patience, fun); one twin seeming withdrawn or anxious around the other; conflicts between the twins that always result in one twin winning; one twin making self-deprecating comments like "I'm the dumb one"; or the twins actively competing to be the "favorite" by trying to outdo each other rather than enjoy their own strengths. Pay attention to the small moments. Do you use pet names with one twin more than the other? Do you make eye contact and listen when one twin speaks but interrupt the other? Do you remember details about one twin's interests but forget the other's? These micro-behaviors accumulate and teach children which of them truly matters to you.
Why Individualized Parenting Actually Strengthens Twin Bonds
Parents often fear that treating twins as individuals will weaken their twin connection. The opposite is true. When parents encourage each twin's separate interests, spend one-on-one time with each child, and avoid constant comparisons, twins actually show greater willingness to share and care for each other, and their bond strengthens rather than weakens.
The research is clear: the American Academy of Pediatrics recommends that parents actively recognize and foster each child's unique interests and talents to support healthy identity formation alongside twinhood. Individual recognition is a developmental necessity, not something to apologize for. A twin who feels secure in their own identity does not need to compete with their sibling for parental approval.
A twin who is allowed to love soccer while their sibling loves art does not feel inferior—they feel seen. These secure twins often become close friends as adults, not defensive rivals. The mechanism is psychological: when twins feel equally valued as individuals, they do not need to maintain opposition to feel distinct. A "good twin" label creates a defensive identity. A genuine identity—"I like building things" or "I'm someone who thinks carefully before speaking"—can coexist with a sibling who is different without creating estrangement.
Practical Strategies to Protect Against Favoritism
Start by auditing your own behavior for a week. Write down each one-on-one moment with each twin and what you did. Include conversations, activities, praise, and correction. Do the lists look balanced? Are there patterns? This is not about perfection but awareness. Schedule regular one-on-one time with each twin, separate from the other. This does not need to be long—15 minutes of your full attention, twice a week, can make a difference.
Use this time to ask questions about that child's world without the other twin present. A child who gets to talk to a parent alone will share things they would never share in front of their twin. Encourage each twin's distinct interests even if you do not personally understand them. If one twin loves drama club and the other loves coding, attend performances and ask about code projects with equal enthusiasm.
Do not let one interest trump the other in your schedule or attention. If schedules conflict, alternate which events you attend, not always the same one. Stop comparing the twins, even in positive ways. "Your brother is so good at math—you should ask him for help" sends the message that your brother owns math and you do not.
Let each twin struggle and succeed at their own pace in their own domain. Correct behavior without character judgment. Never say "You are the difficult one" or "Your sister is so much easier." Instead, address the behavior: "That choice did not work. What would you do differently?" This keeps the child's self-image open and changeable.
Create separate friend time for each twin. A twin who only socializes with their sibling may struggle to develop an independent identity. Encourage each child to have friends outside the twin relationship and time with those friends separate from their twin.
Repairing Favoritism That Has Already Happened
If your twins are already showing signs of damage—anxiety, behavioral problems, or emotional distance from each other—intervention can help. The first step is acknowledgment. You do not need to confess to your children that you played favorites, but you do need to change the pattern visibly. Start with the twin who feels less favored. Increase one-on-one time dramatically.
Ask them about their interests, their worries, and their dreams without the other twin present. Notice and comment on their specific strengths. This is not about overcompensating or being obviously different to the other twin—it is about rebalancing so the child feels genuinely seen. Address the "good twin / bad twin" dynamic by refusing to reinforce it.
When one twin behaves badly, respond to the behavior, not the twin. When conflicts arise, do not automatically side with the "good" twin. Insist that both twins are capable of making mistakes and good choices. This slowly dismantles the fixed identities. Family therapy is worth considering if the twin estrangement is severe or if one twin shows significant anxiety or depression.
A therapist can help siblings build empathy for each other and break learned patterns of opposition. They can also help you understand your own unconscious biases and reactions. Give the process time. Twins who have internalized opposite identities did not learn those identities overnight. Changing them takes months, not weeks. Consistency matters more than dramatic gestures.
How Needs and Fairness Change With Age
Favoritism in infancy usually looks like one twin receiving more feeding time or more soothing because that baby is fussier. This is responsive parenting, not favoritism, but it can feel unfair to the other baby. Explanation helps: "Your sister is hungrier right now, and you will get your turn in just a moment." Even babies understand turns.
By ages three to five, favoritism becomes more visible because twins have distinct interests and abilities. One might be toilet-trained early and the other later. One might be social and the other shy. Parents who treat these differences as neutral—neither better nor worse—protect against damage. One who treats early toilet-training as "advanced" and late toilet-training as "babyish" is setting up a hierarchy.
In elementary school, academic and athletic differences become pronounced. This is when the "smart twin / athlete twin" divide often solidifies. Actively work against it by asking each twin about their own progress, not comparing them. Celebrate different achievements equally: an A on a math test is not more valuable than a goal scored in soccer.
Adolescents need autonomy and identity formation. Twins at this age benefit enormously from permission to be different. One might want to dress like a goth and the other like a jock. One might be dating and the other focused on friendship. Let these differences exist without judgment or comparison. The fairness standard changes: very young children need equality (equal portions, equal time).
Older children need equity (what each child actually needs). A ten-year-old with anxiety might need more parental support than a confident ten-year-old. This is fair, not favoritism.
When to Seek Professional Help
A therapist should be consulted if one or both twins show persistent anxiety, behavioral problems, low self-esteem, or difficulty forming relationships outside the twin bond. These are signs that something in the family dynamic needs professional attention—favoritism may be the cause, but there may be other factors too. Signs to watch: a twin who refuses to go to school, who has frequent meltdowns, who injures themselves, who withdraws socially, or who makes statements about not being loved or valued.
A twin relationship so hostile that the children cannot be in the same room without conflict. A twin who regresses developmentally (loses toilet-training, loses language, becomes clingy after being independent). Family therapy is different from individual therapy for a child. A family therapist works with all of you to change patterns of interaction, not just to "fix" one child.
This is especially valuable with twins because the problem is relational, not individual. A psychiatrist may be needed if anxiety or depression is severe. These conditions are real medical problems, not character flaws or signs of failed parenting, and they respond to treatment. Getting help is not an admission of guilt—it is good parenting. Prevention is more effective than repair.
If you catch differential treatment early and change your patterns, you avoid the entrenched identity divisions that take much longer to undo. But if you are reading this because you are worried you have already caused damage, know that change is possible. Twins are resilient, and parents who recognize a pattern and commit to changing it give their children the gift of repair.
Frequently Asked Questions
Is it favoritism if I spend more time with one twin because they need more help?
Not necessarily. Responsive parenting means adjusting to each child's actual needs. A child with learning difficulties may need more homework help; a child with anxiety may need more reassurance. The difference becomes favoritism if the child receiving less support feels it as rejection, or if you use it as evidence that one twin is less capable. Counter this by also spending one-on-one positive time with the child who needs less support.
My twins are identical, so shouldn't I treat them the same?
Identical genetics do not mean identical personalities or needs. Identical twins often develop different interests specifically to feel individual. Treating them identically can actually force them into artificial sameness and rob each of them of their own identity. The goal is equal valuing, not identical treatment.
When does normal sibling conflict become a sign of favoritism?
All siblings argue. Favoritism is suggested when one twin consistently wins conflicts regardless of who is at fault, when the twins seem afraid to disagree around you, when one twin seems anxious or withdrawn in the other's presence, or when one twin makes self-deprecating statements about always being the "loser" in the family.
Can I repair favoritism if my twins are already teenagers?
Yes, but it takes longer because identity patterns are more entrenched. Increase one-on-one time with both twins, refuse to reinforce the "good twin / bad twin" divide, acknowledge that you have noticed the pattern (you do not need to apologize, but you do need to change visibly), and consider family therapy to help both twins work through learned resentment.
What if one of my twins is genuinely easier to parent?
Many children are temperamentally easier or harder. The key is not to let your easier relationship with one twin become invisible favoritism toward the other. Make a point to spend separate positive time with the harder-to-parent twin in settings where that child succeeds. Find one thing that child is interested in and engage with it. Your goal is to balance the dynamic, not to pretend both twins are equally easy.
How do I recognize if my twin is developing anxiety or depression from feeling less favored?
Watch for persistent sadness, anxiety that interferes with school or friendships, withdrawal from activities they used to enjoy, self-critical language ("I'm the bad one"), sleep or appetite changes, or statements about not being loved. These warrant a conversation with your child's pediatrician or a therapist, regardless of the cause. Feeling less favored is one possible contributor, but there may be others.
