Families, particularly larger ones, are always sources of conflict.
Sure, all is forgiven in the end, but if you have brothers or sisters it's likely you grew up in a competitive environment that puts most offices to shame.
Unfortunately (for all you younger siblings out there) it looks like the firstborns of the family have had an even greater headstart than you realised.
Firstborns have been found to have great thinking and cognitive skills compared to their younger siblings.
Researchers from the University of Edinburgh believe that is because they received more mental stimulation from their parents.
The authors of the research were quick to point out that parents give all their children the same levels of emotional support, but the privileged Child Number One generally receives more support with tasks that develop thinking skills.
Economists at the University of Edinburgh, Analysis Group and the University of Sydney examined data from the US Children of the National Longitudinal Survey of Youth.
From pre-birth to the age 14, close to 5,000 children were observed and assessed every two years.
The tests covered literacy development and vocabulary, and also noted family background and the economic conditions the child grew up in.
The results revealed that firstborns scored the highest in almost all of the tests - with the most noticeable improvement in abilities recognised around toddler age.
The study also reports that many parents changed their behaviours as they had more children, which resulted in less mental stimulation and other activities that had previously helped the firstborn's excellent test results.
Dr Ana Nuevo-Chiquero, of Edinburgh University’s school of economics, explained:
Our results suggest that broad shifts in parental behaviour are a plausible explanation for the observed birth order differences in education and labour market outcomes
If you're a firstborn and you're reading this, don't forget to bookmark it and bring it up at the next family gathering.
For all of the younger brothers and sisters out there, you're probably much cooler and able to get away with more, so it evens out, right?