• We hear a lot about the impact of our relationship to our parents – but what about our siblings?

  • Birth order theory suggests that where we fall in the family can affect personality into adulthood

  • If your childhood experiences negatively affected your sense of self, find a therapist here 

Whether you’re the eldest, a middle, the youngest or a single child can have a powerful impact on your character. Your character is shaped by many factors of course, many of which may be more significant, including what resources your parents had, and what relationship you had with your caregivers, your genetic makeup and how your brain works. Nonetheless, your sibling relationships are significant, especially given your position in the family is continually reinforced throughout your life.

To gain a realistic picture of how and why birth order can make a difference, let’s start with the qualities that, in broad terms, are characteristic of each birth order position.

First borns

You are the only child in a family who enjoyed the undivided attention of your carers, only to lose it later to a new sibling. You therefore grow up determined to regain that lost attention, and therefore to please those in authority (in essence, parental figures) and to become a leader/authority figure in your own right. 

The time you had as the sole object of your parents’ attention means you had excellent exposure to language, so you’re likely to be a good communicator and to do well in school. You probably helped care for your younger siblings (to regain some parental attention!), so you’ll be good at nurturing and caring for others. 

However, because your parents were ‘new’ to parenting with you, they will have been more anxious, so you, too, are likely to be more anxious than your younger siblings.

Middle borns

You will be good at getting along with others, because you will have had to share parental attention from the moment you were born. Because your parents are now more experienced and calmer you’re probably less anxious than your older sibling, and because you grew up surrounded by peers you’re likely to hold more realistic expectations about yourself than will your older sibling. 

At the same time, because as a child you concentrated so much on compromise and social harmony, you may not know very clearly what you really want in life, and you can be plagued by lack of direction. 

Finally, you’re the person in the family who’s most likely to take up causes for the underprivileged, or to support the less fortunate. This may be because you felt left out at times when you were growing up--you can empathise with those who are often overlooked.

Last borns

You are born to the most experienced parents, parents who by now probably allow more latitude when disciplining their offspring. This means that when you tested the family boundaries—something all children do—you were pushing against wider limits than were your older siblings. You therefore become more of a risk taker. 

You’re also likely to be more creative and less conventional, particularly more so than your eldest sibling. At the same time, you may feel conflicted about growing up, particularly if your parents were reluctant to let go of their parenting role, and you can feel easily let down by others when they don’t treat you as ‘the baby’ and offer help and support. 

Finally, you’re likely to be charming and outgoing, the entertaining, cute one — again, reflecting your role as the ‘baby’ in the family.

Single child

You, like the first born, enjoyed undivided parental attention. However, you never had to lose it to a sibling, so you never had to experience such intense jealousy. Growing up in an adult world, you’re likely to be a good communicator, practical, academically able, and happy to spend time on your own. At the same time, you may feel somewhat awkward with peers, preferring the company of people older than yourself. You may also find it difficult to tolerate disorder.

The descriptions given above are a starting point to help you begin to understand character development. However, to create a more realistic picture of how your birth order position has helped shape your character, we need to consider two further factors:

The gender of your siblings

Even when they try not to, parents treat their daughters differently from their sons, and they hold different preconceptions about them. Parents also (naturally!) are quite excited when the first child of the other gender is born, so that child will in many ways be treated as a first born. If there’s only one sibling whose gender is different in a family, he or she is especially likely to receive extra parental attention, and that will probably continue throughout childhood. 

Another way gender can make an impact is that pairs of siblings are more likely to compete if they’re the same gender, particularly if they’re also close in age. Finally, when there are both boys and girls in a family, it seems that some gender-specific characteristics of one group exert their influence on the other. In particular, when there are more males than females, the females tend towards more tomboyish behaviour; and when there are more females than males, those males are often more nurturing and emotionally sensitive than other men.

The age gaps between siblings

If you are part of a close age gap—that is, less than two years—it means that you had a playmate and companion during much of your childhood. At the same time, however, because you both had roughly the same needs at the same time, you also competed with your sibling for parental attention—so probably you argued with and felt jealous of him or her. That said, you’re more likely to be close friends as adults and to regard one another as equals. 

A larger age gap—more than four years—is generally enough to ensure that the needs of any two siblings don’t overlap much, so there will be less competition and rivalry between such sibling pairs. In fact, the relationship that tends to develop between siblings who are widely spaced is more of a ‘carer/cared for’ than a peer relationship.

A note on blended families

Introducing more children into a family is a difficult challenge at the best of times. The qualities that each child has developed as a consequence of their birth order position is unlikely to change substantially, unless the child is very young. That’s because we establish the foundations of our identity between the ages of about three and six. 

In the longer term, the key to harmony in a blended family depends almost entirely on how the parents of this new blended family handle the settling down period. Parents need to present a united front, they need to back up one another, they must endeavour to treat all the children consistently and fairly, and they need to praise each child — frequently and sincerely —  for his or her unique talents and contributions to the new family. A tall order, it’s true, but a possible one!

Linda Blair is a chartered clinical psychologist and associate fellow of the British Psychological Society

Further reading

How to handle sibling rivalry

How I overcame my family history with therapy

Family constellations: the invisible ties that bind us

This is what happens when you visit a family therapist

When siblings get left behind