Psychologist breaks down key differences between oldest and youngest children and lists four things parents 'should do' for their kids

If your sibling constantly used to tell you you're adopted because you're so different to the rest of the family, this one's for you.

Despite the baby books, birth certificates, and your parents saying otherwise, many of us have probably experienced our sibling telling us we were, in fact, adopted.

Now, you may've ended up harbouring this as a hushed fear for over a decade until you grew up and realized they were just twisting your arm, or maybe you marched straight away up to your mom and dad to demand the truth, but sometimes, it can be hard to question how on earth you and your siblings were brought up in the same household when you turned out so vastly different.

And as there always seems to be, there's a theory for that.

There can often be some noticeable differences when it comes to oldest and youngest children (Getty Stock Images)

Differences between oldest and youngest child

Now, while the 'birth order theory' isn't grounded in official medical or psychological diagnosis, psychologist Dr Kate Eshleman explains via the Cleveland Clinic there can end up being some key differences between the oldest, middle, and youngest child.

She explains: "The general concept of birth order theory is that where in the family the child is born is going to predict or determine what their personality style is like."

Now, someone's personality is ultimately impacted by a whole host of other factors too - life experience, genentics, where you're born, and how you develop and maintain over time, but there can be certain patterns which emerge when it comes to oldest children versus middle and youngest.

Oldest, for example, can end up being more 'responsible, intelligent, ambitious, successul, confident, and well-behaved' but also 'bossy, stubborn, perfectionist, and competitive'.

How do you and your siblings differ? (Getty Stock Images)

On the other hand, the youngest child can end up being more 'social, outgoing, rebellious and carefree', alongside 'spoiled' and a 'free-thinker'.

On the difference between older and younger siblings, Dr Eshleman reflected: "The time and attention that parents give early on to their oldest child promotes that early academic development. Younger siblings might not have that, but while they may not be receiving attention from parents, they’re often getting it from their siblings."

But how can parents try and navigate this?

Having multiple kids comes with additional considerations for parents (Getty Stock Images)

How to approach parenting your different children

Well, Dr Eshleman said: "How you parent your child can play a role on the type of personality and behavioral traits they develop."

First up, the psychologist notes parents tend to be 'more anxious' when it comes to their first child and subsequently can end up being overprotective.

This can differ when a parent goes on to have other children, as the parent may potentially have 'more time on their hands to focus on their first child,' but then easing off with the children to follow.

Second, Dr Eshleman notes the more children someone has, the easier it gets to realize 'they're not quite as fragile as you thought', and maybe they don't need as much swaddling as the parent exhibited with their first baby, leading to a potential change in 'parenting style'.

Up next is making sure you don't just treat each of your children the same - they're 'born with temperaments that start from an early age' and will have different needs to the other, so try and listen in and 'respond to their needs' directly.

However, while accounting for the differences, it's important to make sure each and every child still feels like they've been given the same level of attention, care, and 'similar opportunities' to help 'try to avoid any of [the stereotypes above] or that sibling rivalry'.