We know that children with an older sibling who performs well at school can benefit from a knock-on effect. But the order children are born in may affect their personalities as well as their chance of academic success, as this video from ASAP science which gives an overview of current theories about the issue shows.
Older children are considered more responsible, while middle-born children are more corporative, flexible, sociable and able to make and maintain relationships. Those born last tend to be charming and likeable, creative and confident but are also less responsible than their older siblings. Finally, only children are seen as more responsible and mature, but can have trouble relating to their peers.
As the presenters of the video, Mitchell Moffit and Greg Brown, point out: "Some aspects may be true for you, or make a lot of sense, it wouldn't be the same for every single person around the world in your specific birth order. It's important to remember that your personality and your destiny in life is not predetermined at birth."