The oldest is the smartest. The youngest gets it easier. The middle child feels left out.
We've all heard these sibling stereotypes hundreds of times, but is there actually any truth behind them?
According to Michael Grose, parenting educator and author of 'Why First Borns Rule the World and Last Borns Want to Change It', the answer is yes.
"There are birth order positions and birth order personalities which can help explain the differences between kids," Grose told HuffPost Australia.
"Traditionally there are three or four. So there's the eldest, there is the second or middle child, who share similar characteristics, and then there's the youngest.
"An only child is really a first born that has never been dethroned."
And while 'dethroned' may seem like a strong term for gaining a brother or sister, it also makes total sense. Where once the baby had the sole attention of both their parents, now he or she has to share it with a younger, needier individual. And so the concept of 'sibling rivalry' begins.
"If you're first, you are first in every sense. You're the boss, you're you're the king," Grose said. "You have both parents looking at you 24/7 as a baby and life is really good. Then a second one comes along and you have to move over. There is rivalry for attention and affection.
"And there is rivalry there. There always has been and there always will be. How much it plays out depends on the kids' temperament and personality, as well as parenting style and gender."
The other thing that Grose says tends to happen is parents grow more relaxed the more children they have.
"We learn through our first one. It takes us into new ground," he said. "We kind of 'get' parenting by the third or the fourth. We relax and loosen up as we move through the family and have more kids."
So what does all this mean?
"Firstborns get a lot of perks and privileges. It's a good position to be in, but they are often pushed and prodded to perform. As a result, they don't tend to be risk takers. They might do well -- they like to achieve -- but they are low risk takers," Grose said.
"Second-borns are more flexible because their life always fitted into the life of the first born. I'd also put money on the second born to leave the family first.
"A second born has a lot more friends than firstborns. They will reach outside of the family [for attention] and create their own circles."
Grose also said that youngest children tended to outperform the rest of the family, but on their own terms.
"If you are an academic family, there's a reasonable chance your first born or even second born will be an academic and shine, and there's a reasonable chance the youngest one may go down a completely different path.
"They are the most likely to say 'I'm going to run my own business' or 'I'm going to be a tradie'. They tend to go their own way a little bit more. However in saying that, they can also hold themselves back until the older ones leave."
Grose puts this down to always being picked on or being silenced by their older brothers and sisters.
"The way a lot of families work is, when the first born said something cute, the parents and grandparents paid complete attention and [celebrated] that.
"When the youngest one says the same thing, one of their older siblings will most likely turn around and say, 'You dickhead, what a stupid thing to say'. So they will learn to hold themselves back."