Science has just confirmed what older siblings reckon they knew all along: that first-born children are more intelligent than their younger siblings.

Finally settling the age-old debate about whether birth order really influences a child’s intelligence, researchers at the University of Edinburgh found that older siblings scored higher on IQ tests than their younger brothers or sisters.

And the differences in intelligence were obvious even from their first birthdays, with older siblings getting higher scores on a range of tests including reading, picture vocabulary tests and letter matching.

The researchers, who assessed almost 5,000 children every two years from birth to the age of 14, attributed this higher intelligence to older children getting more mental stimulation from their parents than their younger siblings.

They found that parents engaged in fewer activities with their children the more they had, meaning they did things like reading and making crafts with their oldest child more than their younger siblings.

It's official: science confirms triumphant fact about older siblings