Sorry to the middle kids and babies of the family...
A new study from the University of California saw that from 384 families quizzed, 74 per cent of mothers and 70 per cent of fathers had a definite favourite amongst their children.
And while they were not asked to name their favourite child at first, follow-up research between the children of the family sensed eldest children were preferred almost by all.
The result surprised researchers, who had been aiming to prove the youngest children were the favourite.
The bias towards first-born children affected the confidence and self-esteem of younger siblings.
But while younger siblings may be annoyed that first-borns may be the favourites, there have been studies that show siblings do improve the quality of life.
Previous studies from the University of Toronto discovered having an older sibling could help to boost intelligence, while other research from Ohio State University said growing up with brothers or sisters may also make divorce less likely as an adult.