In an unexpected development, academics at Notre Dame University have discovered that children born at least two years before their younger brother or sister scored consistently higher grades in math and reading than those who were born closer together.

The benefit of waiting was most evident between the first and second born children, the new study found. Research also revealed that periods of atleast two years between the birth of subsequent children was also beneficial for the elder of the two.

Kasey Buckles, an assistant professor of economics at Notre Dame, told The Australian: 'We believe this is the first time anyone has established a causal benefit to increasing the spacing between siblings."

The new study will be published in the Journal of Human Resources, where data from more than 3,000 women and 5,000 children was carefully analyzed.

Researchers reportedly studied the birth order and spacing between siblings in relation to their achievement scores in math and reading aged between five and seven years old. Consistently, the new study found the elder child's results were best if there was a two-year gap - but the results did not improve if the gap was any longer.



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The average child in the study could read 22 out of 84 words; elder children who were born two years before their younger brother or sister could read an average of four words more than their peers who had been born closer together. Researchers saw a similar trend in the children's math results.

Experts believe the difference in academic achievement is most likely linked to the amount of time and resources parents can invest in a child before a younger sibling arrives. A clear developmental marker was also found between siblings born in less well off homes.

"The two-year gap is significant because the early years are the most important in a child's development - so dividing your time when the child is one is more harmful than dividing it when the child is already in school," said Buckles.