New research has found that the eldest child is usually the most intelligent, and it's probably the fault of the parents.
Researchers from the University of Edinburgh reckon they've solved the age-old question with their findings which show that first-born have a higher IQ.
As a youngest sibling, I reckon this is bullshit; my older brother once got his head stuck in a saucepan.
The researchers said that the reason could be because parents are more likely to lavish attention and mental-stimulation on their first born and seemingly can't be arsed by the time it comes to the subsequent children. Thanks mum, thanks dad.
The results were published in the Journal of Human Resources and could go some way to explaining the 'birth effect order' which shows that the oldest child often has a higher paid job and better education.
The study looked at almost 5,000 kids from pre-birth to 14, who were tested every two years on their skills including vocabulary and reading.
Dr Ana Nuevo-Chiquero of the University of Edinburgh's School of Economics said: "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."
Don't worry fellow youngest-siblings, because research has previously shown that we are funnier.
In a study conducted by YouGov it was found that 46 percent of youngest siblings believed they were funny compared to only 36 percent of elder siblings.
Younger siblings are more likely to feel favoured by their parents, but that might just be because we're better people.
Reckon William's cleverer and Harry's funnier? Credit: PA
The eldest sibling is also more likely to feel more responsible - 54 percent compared to just 31 percent of youngest siblings say they are responsible.
The study concludes: "To some extent age itself, rather than family dynamics, may be responsible for the differing characteristics. Older children, having had more time to get on in life, are more likely to say they are more successful than their siblings.
"But undoubtedly there are family forces at work - parental attention soon shifts onto new arrivals, and first borns may have to learn the ropes themselves. As evidence, elder siblings are more likely to feel more organised and able to prioritise their own lives."
Us younger siblings are also more likely to describe ourselves as 'easy going' and 'relaxed'. Which is handy considering we're stupid and won't earn as much.
Featured Image Credit: Fox / The Simpsons