Birth Order Theory: Insights Into Your Personality

Medically reviewed by Karen Foster, LPC
Updated June 18, 2024by BetterHelp Editorial Team

Personality can develop from various sources and influences in a child's life, including birth order. Studying personality and its formation has interested researchers, psychologists, and scientists for centuries. Enduring characteristics, traits, and behavior can shape each person's unique adjustment to life.

Birth order theory suggests that while personality is mainly unpredictable, specific general characteristics can be linked to a person's birth order in their family. Birth order refers to the rank of siblings in relation to age. It's thought that parents intentionally or unintentionally assign roles based on birth order, which may impact a child’s personality development.

In this article, we'll explore the theories and studies behind personality development, focusing on birth order theory.

Getty/Luis Alvarez
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Birth order theory: Why it matters

Theories on personality formation, adaptation, and environmental influences across cultures vary. The concept of birth order is often credited to Austrian psychoanalyst Alfred Adler in the early 1900s. He was one of the first to explore the idea that a person's place in their family tree could predict personality traits. 

Adler believed that firstborn children typically have higher expectations placed upon them by parents and thus develop a greater sense of responsibility and ambition. He proposed that later-born siblings, on the other hand, were often treated more leniently by their parents compared to firstborns, leading them to become more rebellious and independent.

However, it is important to note that Adler's theories are not universally accepted, and a person's place in their family tree does not always dictate their personality traits. Ultimately, each person is unique and should be treated as such. Each person has strengths and weaknesses independent of their birth order.

What birth order theory is not

Birth-order personality traits are not necessarily present when a child is born into a family. For example, firstborn children are not necessarily born with niche or particular personality traits ingrained in their psyche. Instead, in birth order theory, Adler illustrates how family environments and dynamics can shape individual psychology during a child's formative years. Although every family is different, there are similarities in the interactions between parents and children and siblings.

The family's role in birth order personality traits

Birth order research and studies show several influences shaping personality in addition to birth order. Common factors include:

  • Biological: Children tend to inherit many traits and features from their parents. These can include intelligence, courage, and physical characteristics.
  • Social: By interacting with others in an individual's social circle, children learn behaviors and thought patterns from their experiences, like those in the education system and beyond.
  • Cultural: A child growing up within a culture consciously or unconsciously can adopt traits consistent with the culture's beliefs, ideas, and norms.
  • Physical Environment: An individual's surroundings often impact the development of personality. For example, the personalities of those growing up in a rural area may differ from those living in an urban environment.
  • Situational: As a child grows up, they face different situations, which may help them adapt and change their personality. These situations could include meeting new friends, experiencing trauma, or welcoming a new sibling.

When looking at these factors, we see family life can incorporate all of these. Since most children's lives are, at first, shaped by everything going on in the family, it makes sense that some psychologists have remained interested in birth order theory throughout the years since Adler first proposed his idea.

How birth order may affect personality

The following traits are general examples of how birth order differences and personality may be related. Of course, many other factors could impact the development of a child's personality; some of these reasons will be discussed further below.

Only child

These children tend to get much more attention from adults than a child with siblings does. This means many of their early interactions involve individuals significantly older than them. These interactions can make them feel like "tiny adults," and they can seem more mature than their peers with siblings. Traits may include:

  • Confidence
  • Maturity for their age
  • Sensitivity
  • Use of adult language
  • Self-centeredness
  • A tendency to enjoy being the center of attention
  • Refusal to cooperate with others
  • A tendency to feel unfairly treated when not getting their way
  • A desire to be more like adults, so may not relate well with peers
Getty/Xavier Lorenzo

First child

Since the firstborn child is used to being an only child until siblings come along, they may exhibit some of the characteristics of an only child. Also, the firstborn may have these birth order personality traits:

  • Achiever and leader
  • Feelings of superiority over other children
  • Difficulty when the second child is born, such as feeling unloved or neglected
  • A tendency to be controlling and focused on being correct about results
  • Use of good (or bad) behavior to regain parents' attention
  • A tendency to be bossy or authoritarian about rules
  • A desire to please others
  • Reliability

Second child

Second-born and middle children begin their lives with their parents' attention on the firstborn. Having an older sibling as a role model makes second-born and middle children try to catch up with older children. Adler believes the second child can be better adjusted. A second child may:

  • Be more competitive
  • Lack of the undivided attention of parents
  • Be a people pleaser
  • Be a peacemaker
  • Develop abilities the first child doesn't exhibit to gain attention
  • Be rebellious
  • Be independent and not need the support of others

Middle child

Many have heard of the "middle child syndrome" and the difficulties these children can present. They may become frustrated or resentful of the significant changes they experience early in life. Not only do they lose their "youngest child" status, but they also must compete for attention with older and later-born children. 

Middle-born children in larger families are typically less competitive than single middle children. Their parents' attention can be spread thinner due to the dynamics of a bigger family. Middle children in bigger families may be more prone to use cooperation to get what they want. Middle children may demonstrate the following tendencies:

  • Can feel life is unfair
  • Can be even-tempered
  • May feel unloved or left out
  • May not have the rights and responsibilities of the oldest sibling or the privileges of the youngest
  • May be adaptable
  • Can be impatient
  • May be outgoing and rambunctious
  • May treat younger siblings more roughly
  • Can feel "squeezed" in the family environment

Youngest child

The "baby" of the family tends to get more attention from parents since the older siblings are developing and becoming more independent. Traits of the youngest child may include the following:

  • May be charming and outgoing
  • Can be an attention seeker
  • Behaves like the only child
  • Feels inferior, like everyone is bigger or more capable
  • Expects others to make decisions and take responsibility
  • May not be taken seriously
  • Can become "speedier" in development to catch up to other siblings

Other factors that may influence birth order personality

Each family is different and has unique dynamics. The subject of birth order positions alone will not determine the complexities of a person’s personality. Certain circumstances or measures may impact a child's personality as children and families develop and evolve. Across different families, children of the same birth order can show diverse personality differences, especially across a large representative sample.

Blended or step-families

When two parents remarry, especially when children are in their formative years, the family of origin often goes through a period of disorientation and competition. For example, two firstborns in the new family may search for their "place" and may compete to keep their "firstborn status."

Differences in ages

When there is an age gap of three or more years between siblings, it is common for the birth orders to restart. In a family with many children, this could create birth order subgroups with varying birth order effects.

Health and mental issues

A child born with significant physical or neurodevelopmental disabilities can seem to remain in the "youngest" position regardless of birth order. It may impact the psychological birth order position of the other children.

Gender of siblings

Most psychological competition tends to occur between children of the same gender and similar ages. The competition, partly for parental attention, can start in childhood and move into young adulthood and beyond.

Death of a sibling

The impact of a child's death can be devastating for families. Some children may adapt by developing overindulgent tendencies. Also, a glorification of the deceased child can occur, whereby other siblings may never live up to the image of the deceased sibling. It can profoundly alter the birth order effect.


An adopted child often has special circumstances in the family dynamic. Having an adopted child may be seen as a special gift for parents with difficulties conceiving. These parents may have a greater tendency to spoil or overindulge the child. When an adopted child comes into an established family, they may find difficulties fitting into the dynamic.

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Does a correlation between birth order and personality exist?

Multiple factors, including socioeconomic status, parental attitudes, gender roles, and social influences, can also shape an individual's personality. In a study of more than 20,000 participants, however, details revealed no significant effects of birth order of the Big Five personality traits: extraversion, emotional stability, agreeableness, conscientiousness, and openness to experience.

However, some research has linked higher intelligence to a family's older children. It could be because parents have more emotional and intellectual resources to give when fewer children are present in the home.

While birth order may sometimes influence personality traits, no one factor can definitively explain them fully. Many interrelated factors likely play a role, including genetics, family dynamics, and the individual's environment.

Gain additional insights into your personality in therapy

If you’d like to gain more insight into your personality or how your birth order shapes it, consider working with a mental health professional. With a therapist, you can explore how your early childhood experiences shape your current behavior and develop coping skills to help you navigate life’s challenges. Your therapist can also provide evidence-based strategies for managing challenging emotions and building healthy relationships.

If you are not interested in traditional in-person therapy, consider using online counseling through BetterHelp. Online therapy can be a convenient way to get mental health care. Research suggests that online treatment is as effective as in-person therapy and can often fit into your schedule more easily. You can speak with a therapist from your home or anywhere you have internet connection.


Birth order does not necessarily determine an individual’s personality, but it can be a contributing factor. Consider getting professional support if you are struggling with your birth order and its effects on your life. A qualified therapist can provide valuable insight and tools to help you navigate life’s challenges. With support and guidance, you may learn to appreciate your unique place in your family and manage any negative feelings that may arise.
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