Only child syndrome is a theory referring to certain characteristics that people may associate with being an only child. However, there is no reliable evidence that being an only child significantly affects personality or behavior. Therefore, current research states that only child syndrome is not real.

The only child syndrome theory suggests that a child without siblings may be more likely to lack social skills and be spoiled, lonely, or selfish.

This article looks at whether only child syndrome is real and if there is any evidence behind the stereotypes of only children.

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Only children syndrome is the term for the negative traits that people may associate with children with no siblings. These traits can include selfishness or loneliness.

The idea of only child syndrome may originate from the work in the 1800s of child psychologists, including E. W. Bohannon. He administered questionnaires exploring the traits of children without siblings and found that the overwhelming majority of respondents described negative attributes.

Bohannon’s survey in the late 19th century included 200 participants who described only children as spoiled and overly sensitive. This inaccurate finding seemed to take hold during this time. More specifically, there were concerns that only children could be overly sensitive. Additionally, due to their parents’ excessive focus on them, they could develop issues such as hypochondria.

Very little recent scientific research suggests that only child syndrome is real.

Recent research suggests that there are still negative perceptions around only children, including that they are less altruistic than children with siblings. Altruism is the practice of acting for the benefit of others and putting their needs before their own.

Although the stereotype of only child syndrome may be prevalent, the evidence suggests the stereotypes are inaccurate.

Certain inaccurate beliefs exist around the idea of only children, which may originate from research from the past and cultural stereotypes. These ideas suggest that only children may be:

  • coddled or over-indulged
  • spoiled
  • selfish
  • lacking in social skills
  • overly sensitive
  • used to receiving excessive attention from parents

However, there is no recent evidence to suggest that being an only child will cause people to have these characteristics. According to research, being an only child does not have associations with negative outcomes in many areas of life.

A 2021 study included 227 mothers of 342 children to examine whether being an only child or having siblings affected:

  • the children’s school attendance
  • the parent’s psychological state
  • the parent’s response to their child’s reports of stomach pain

The researchers found that it was more likely for parents of only children to minimize a child’s symptoms of stomach pain compared with parents of children with one sibling or more.

The study also found that school attendance was better in only children and that it was more likely for children with siblings to miss school.

These results go against the idea that parents may overprotect or coddle an only child. This research suggests that parents of only children may be more likely to discount or minimize an only child’s reports or symptoms of pain or illness. They may also be more likely to send them to school even when their child feels unwell.

One possible explanation for this is that parents of only children do not have other children to compare symptoms with. Conversely, parents of multiple children may make comparisons between the health of siblings.

The study concluded that parents with only children were no more protective than those with more than one child. This finding may go against some stereotypes about being overprotective of only children.

A 2018 study compared behavior traits of only children and children with siblings in Beijing as well as the influence of gender and China’s one-child policy.

The study notes a stereotype of only children in China as being egocentric and “little emperors.” This theory may stem from the idea of having excessive levels of care from multiple adults, such as parents and grandparents. This led to concerns about negative effects on a child’s development.

The study consisted of 1,000 school-aged children. The child participants, their peers, parents, and school teachers assessed their attributes according to a checklist of school-age-appropriate behavioral attributes.

The results showed that male only children evaluated themselves less positively. Additionally, peers, parents, and teachers also evaluated them less positively compared with female only children.

Male only children evaluated themselves more positively in terms of self-enhancement than their peers evaluated them. Self-enhancement is a person’s tendency to have an unrealistically positive view of their own qualities.

This research suggests that beliefs around only children may affect how children and others see themselves.

Research focused on only child brain development

A 2016 study found that only children scored higher on flexibility, suggesting greater creativity, and lower on agreeableness than children with siblings.

The study found that there were notable differences in certain regions of the brain between only children and children with siblings that may affect behaviors relating to creativity and agreeableness. The researchers concluded that being an only child or a child with siblings may impact the development of brain structure and behavior.

A 2019 study suggests that there is still a generally negative view of only children, including that they may be more likely to be selfish or narcissistic.

People generally see narcissism as a negative or undesirable trait, so they may dislike others they deem narcissistic.

This research suggested that children with siblings may see only children as part of a separate social group and may view them more negatively. This may lead to different treatment of an only child by their peers or assumptions about the characteristics of only children.

The researchers found no evidence to suggest only children are more narcissistic, so these claims may lead to unjustified judgments against them.

Learn more about narcissism.

Below are answers to common questions regarding only children.

Are single children more selfish?

According to 2019 research, being an only child does not significantly affect most personality traits. The authors also found there is no significant difference in personality between only children and children with siblings.

Research has shown that people may perceive only children as less altruistic than children with siblings. However, the evidence suggests that there is no difference in altruism between the two groups.

How do you socialize an only child?

To support an only child’s social and emotional development, parents and caregivers can ensure they have plenty of opportunities to play and interact with other children. They can also help a child learn and practice how to engage appropriately with other children, for example, teaching how to share, take turns, and help others.

Other tips for social development include:

  • supporting a child’s emotional identification, regulation, and expression
  • providing encouragement and praise to a child
  • setting fair and consistent boundaries and routines
  • actively engaging in quality interactions with a child every day

Older research and stereotypes incorrectly suggest that only children may be more self-centered, narcissistic, or spoiled than children with siblings.

However, there is no recent evidence to support these theories. Researchers suggest there is little difference in the personality traits of only children compared with children with siblings.

Parents and caregivers should ensure that any child has plenty of opportunities to play with other children can help them develop socially.