You may have heard that the oldest child is bossy, the middle child is rebellious, and the youngest child always gets their way—but it probably goes without saying that these are all stereotypes and oversimplifications at that. There are stereotypes about only children, too. According to the theory of "only child syndrome," not having any siblings can make someone more likely to develop certain characteristics.
Certainly, the number of siblings someone has—or lack thereof—may shape their personality, but to what degree? And what is only child syndrome, and is there any validity to this notion? We tapped licensed therapists—and reviewed relevant research—to find out.
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What Is Only Child Syndrome?
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According to Kristie Tse, LMHC, a psychotherapist and founder of Uncover Mental Health Counseling, only child syndrome refers to the idea that only children tend to have a certain set of negative traits, such as selfishness or stubbornness.
This theory can be traced back to 1896 when American child psychologist G. Stanley Hallpublished the results of a national survey he conducted. According to his findings, only children had a long list of negative traits in common—leading him to go so far as to say that being an only child was a "disease" in itself. Needless to say, his work is now viewed as controversial.
Over the last 50 years, child psychology experts have challenged and debunked many of Hall's conclusions.
Common Characteristics Among Only Children
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According to licensed therapists, there are some common only-child traits:
1. Independence
Experts say an only child is naturally more inclined to become self-reliant—after all, they don't have any siblings to hang out with, learn from, or ask for help.
As a result, they learn to take on responsibilities independently, explains Catherine Nobile, PsyD, a clinical psychologist and director of Nobile Psychology.
"As an only child myself, I can attest to the depth of introspection and independence that often develops without siblings," adds Tse. "My personal experience has also shaped my empathy and understanding in my therapeutic practice."
2. Creativity
Since only children don't have siblings to play with, they're forced to entertain themselves.
As a result, only children are often very creative and have a rich imagination, says Natalie Rosado, LMHC, a mental health expert at the Sanity & Self self-care app for women.
"Additionally, only children may develop strong problem-solving skills and a robust sense of self-discipline," adds Nobile.
3. Maturity
Without siblings, only children tend to spend much more time around adults.
"This can lead them to develop a greater level of maturity," explains Kanchi Wijesekera, a licensed clinical psychologist and founder/clinical director at Milika Center for Therapy and Resilience.
According to Rosado, communicating so much with adults rather than peers can also lead to strong verbal skills, as well as a strong bond with their parents.
There can be a negative side to this, though.
"Only children may become overly reliant on their parents for emotional support, leading to difficulties in forming independent peer relationships," says Nobile.
4. Difficulty sharing
Since only children don't have to share toys and other belongings, bedroom space, and their parents' attention, they may have more trouble with sharing, says Nobile.
This can create challenges, such as during playtime with friends or later on when they finally have roommates in college.
"Socially, they might struggle with developing teamwork skills, having had fewer opportunities to navigate sibling dynamics," adds Nobile.
5. Confidence
Competitiveness can sometimes brew in families with more than one child—hence the term "sibling rivalry." But only children don't have siblings to compete with growing up, and therefore, may develop a higher level of self-assuredness.
"The undivided attention and encouragement from parents can bolster an only child's confidence and self-esteem," says Rosado. "They may feel more assured in their abilities and comfortable in leadership roles."
Rosado notes that being an only child may also lead to greater self-awareness. "They spend more time alone, which can lead to a deep understanding of their interests, strengths, and weaknesses," she explains.
6. Perfectionism and sensitivity to criticism
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Many only children are ambitious and driven to excel, says Tse. Why? Because they have more parental attention and support—and since there are no other children to focus on, they may feel a greater sense of pressure to succeed.
In fact, Nobile and Rosado say only children sometimes lean toward perfectionism and may be more sensitive to criticism due to the high expectations of their parents.
Keep in mind, says licensed holistic psychologistScott Lyons, that just because someone doesn't have a younger sister or an older brother doesn't mean they're guaranteed to have these characteristics. There are so many other factors in a person's upbringing that can come into play in the development of their personality—for example, how much quality time their parents spend with them, how they're disciplined, and the overall family dynamics.
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What Does the Research Say About Only Child Syndrome?
A 2019 study of over 20,500 adults disproved the idea that being an only child significantly affects personality. Researchers found that there aren't really any major personality differences between people who grew up with siblings and those without. Only children were slightly more likely to show signs of neuroticism, for example, but they were also more likely to have higher levels of openness.
Due to China's one-child policy—which limited most families to only one child between 1980 and 2015—there has been a wealth of research on the impact of being an only child.
A 2024 study of Chinese children and adolescents aged 9-15 showed that contrary to stereotypes, only children actually show more "prosocial behaviors" than children with siblings. Prosocial behavior can be defined as anything that benefits others, such as sharing, volunteering, donating, caregiving, and cooperating. Researchers concluded that, ultimately, positive parenting styles had far more of an influence on children's prosocial behaviors than how many siblings they had.
Another 2021 study of Chinese fourth graders found that only children are higher academic achievers than their peers who have brothers and sisters.
So, while some studies have found that only children may share certain traits, it's important to acknowledge that those traits aren't necessarily negative.
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So, Is Only Child Syndrome Real?
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There isn't much scientific evidence to support only child syndrome. But what do the experts say about the personality differences between only children and non-only children?
"The experiences of only children are diverse, and their development is influenced by a complex interplay of factors, including parenting style, socioeconomic status, and opportunities for socialization with peers," says Rosado.
For instance, Rosado points out that an only child in an urban area with younger and socially active parents might have access to a wide range of cultural and educational experiences.
"The urban environment might also present more stimuli and structured extracurricular activities, promoting well-rounded development," she explains. "However, the fast-paced urban lifestyle might also bring challenges such as overstimulation or higher stress levels."
On the other hand, an only child raised in a rural area with older parents might have a quieter upbringing, which could be more isolating but also offer more opportunities to connect with nature and foster more self-reliance.
"With older parents, the child might engage in more adult-centric activities and conversations, potentially leading to advanced maturity," says Rosado.
Additionally, an only child raised by a single parent on welfare might develop a strong sense of resilience and responsibility from observing their parent's challenges, but they might also face difficulties due to economic stress and limited resources, says Nobile.
According to Lyons, whether or not the parents are absent or highly involved in their child's life can play a strong role in shaping their personality as well.
"Although there are stereotypes suggesting that only children might be more self-centered or struggle with social skills, these traits are not universally seen and are greatly influenced by individual circumstances and environment," says Nobile.
Is only child syndrome real? The general consensus is no. Just because a person isn't born into a family with multiple kids doesn't mean they're guaranteed to turn out one way or the other.
"While there are certain traits and behaviors that might be more common among only children, these are not inherently negative, nor are they universally applicable," says Rosado. "Every child is unique."
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How Do You Deal With a Child Who Shows Signs of Only Child Syndrome?
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If you have just one child, and you start to notice them developing any of the aforementioned potentially problematic traits, experts say there are many things you can do to encourage positive changes.
"Parents of only children can take proactive steps to ensure their child's well-rounded development by encouraging social interactions, teaching empathy and cooperation, promoting independence, and providing balanced attention," explains Rosado. "It's important to focus on the individual needs of the child and create an environment that supports their growth and emotional well-being."
Here are some tips for supporting the healthy development of an only child:
- Encourage activities that promote collaboration: "Enrolling them in team sports or group activities can help teach the value of sharing and working together," says Tse.
- Arrange regular playdates: Creating opportunities for your child to play with peers at home can foster better social skills like sharing and compromising, according to Tse and Wijesekera.
- Praise good behavior: Positive reinforcement is the most effective way to change behavior, according to Nobile. "Praise and reward instances of empathy, cooperation, and effective conflict resolution, encouraging these behaviors to become habits, says Wijesekera.
- Volunteer with them: Wijesekera suggests volunteering as a family, which can cultivate empathy and foster a sense of responsibility. Consider giving your child different options for volunteering opportunities so they can choose a cause they feel strongly about.
- Model what you want to see: "Children learn a lot by observing their parents," says Rosado. "Engage in games and activities that require taking turns and working together, helping your child practice these skills in a fun and structured way."
- Give them a journal: According to Rosado, journaling is an excellent tool for only children because it not only gives them a safe space to reflect on their thoughts and feelings but also offers an outlet for developing self-awareness and emotional regulation.
- Set realistic expectations: If your child shows signs of perfectionist tendencies, Rosado recommends emphasizing the importance of effort and improvement rather than achievement: "Avoid setting excessively high expectations. Focus on the process rather than just the outcome. This helps your child develop a healthy attitude towards challenges."
Conclusion
Whether there's one child or multiple children doesn't seem to impact their development nearly as much as other factors like the home environment, parental relationships, and level of socialization with peers.
According to Nobile, many only children grow into well-rounded, successful people.
"Moving beyond the myth of 'only child syndrome' allows us to see each only child as an individual, shaped by their environment, parenting, and personal experiences, rather than by unsupported stereotypes," says Rosado.
