Birth Order has played a role in how we are treated. In royal families the oldest are often the ones to inherit the crown and in civilian families the oldest our often the ones to inherit  their parents bagged.

 Being the eldest sibling in a family comes with a large responsibility, parents want their oldest to be prefect so that their younger children can look up to them. As the oldest sister i have to have good grades, a job, and babysitter while my middle school aged sister is able to roll by with failing marks and behavior problems at school.

while the oldest siblings deal with being pressured to be prefect, middle children tend to struggle to fit in with their family and our often over looked due to their older siblings and younger sibling accomplishments and needs. And younger children
 tend to be cuddled and babied for longer periods of time and they are often never aloud to do what their older sibling are doing or have done because their parents will always think of them as their little baby.