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Why Are My Kids So Different?

I love them the same. How did they turn out so differently? We are the same parents with all of them. It is a quandary, isn’t it? Well, your children are different because they are. There are many varying theories.

Do genetics play a role?

Let’s start with genetics. Siblings usually only share 50 percent of the DNA passed down from their parents. That means they are different by 50 percent. Only identical twins share the vast majority of DNA from their parents. 

Does birth order play a role?

According to Dr. Kevin Leman, author of The Birth Order Book, “…whether you were born first, second, or later in your family has a powerful influence on the kind of personality you will be, the kind of person you will marry, the type of occupation you will choose—even the kind of parent you will be.” First borns tend to be organized, serious, meticulous and interested in academics. Middle children can be independent, loyal to their peers, have many friends and can be mavericks. Youngest children are inclined to be charming, lively, enjoy attention, be mischievous and engaging.  

What role do gender similarities and dissimilarities play?

This may seem obvious but, as examples, one sister may be “girlie” while the other may be “tomboyish.” One brother may like sports while the other prefers computers. Brother-sister relationships are likely to have differences as well. Then dynamics play out in the family as well as cultural beliefs within the family.

Does environment play a role?

You probably are aware of sibling rivalry. Children often rival for their parents’ attention, affection, time and love. To avoid competition, they may find their own special niche. Therefore, they often specialize in different talents and interests—sports vs academics vs technology, etc. Then how parents respond to their children is also related to their own interests and preferences. 

Is it possible for siblings to have different family experiences?

This is an interesting concept. Same family but different experience? Let’s say one child is 12 years old when the family moved or a parent lost a job, or there was divorce or even death. The 12-year old’s experience will be very different from the 9-year old sibling’s due to the fact that the 12-year old benefitted from 3 additional intact years. This can contribute to a profound difference in how these two siblings experience their childhoods. 

Are parents’ assessments of their children factors in why siblings develop differently?

If parents perceive one child to be more gregarious than another, it is possible that in a different family, the one that is less outgoing might actually be considered the outgoing child in an alternate family. In turn, this could influence each child’s self-perception and choices in friendships and behavior in school. Despite attending the same school, they may gravitate to diverse social groups, which in turn influences their personality.


This article reviewed many of the possibilities for why siblings can have such different personalities. Whether how they are loved, the role of genetics, their birth order, gender, environment, age during changes in family dynamics, or reactions to how their parents perceive them, it is likely they will each have unique personalities. And the rationale presented is not exhaustive. 

Ideally, our role as parents is to be able to embrace each personality and guide each child to reach their potential—whatever that turns out to be.