If you're not the first born child in your family, then unfortunately we have some bad news for the status of your sibling rivalry... A study from the The Journal of Human Resources claims that firstborn children are smarter than those born further down the line.
"As early as age 1, later-born children score lower on cognitive assessments than their siblings," the study said.
"The birth order gap in cognitive assessment increases until the time of school entry and remains statistically significant thereafter."
"Mothers take more risks during pregnancy and are less likely to breastfeed and to provide cognitive stimulation for later-born children."
"Our findings suggest that broad shifts in parental behaviour from first to later-born children are a plausible explanation for the observed birth order differences in education and labour market outcomes."
The study also concluded that parents didn't stop showing love and affection to their kids the more they had.