Bookworms born not made.

Genes, rather than reading to young children at home, have a greater influence on how they learn to read once they reach school, researchers say.

The study, published in the latest issue of the Journal of Research in Reading, is the first to demonstrate the influence of genes on potential reading ability in children younger than six.

The study of pre-school age twins from Australia, the US, Norway and Sweden followed into their early school years, found genetic variability accounted for most of the differences in skills that predicted later reading ability.

These skills included understanding the sounds in words, familiarity with letters and verbal fluency.

Australian researcher Brian Byrne, professor of psychology from the University of New England in Armidale, stresses that the amount of time carers spend reading to children at home is important.

But the research shows the significance of supporting pre-school age children who are having difficulties with letters and words.

"If a child is reading poorly in part because they are not as genetically well-endowed as other children, we know we will need to work harder and devote more resources to get them up to scratch," says Byrne.

By the end of their second year at school, the Australian children in the study show almost no trace of the influence of their home environment on reading ability, he says.

And the influence of genetic variability actually increases as children get older, he adds.

"We don't know which genes are involved but some of the genes in question affect brain development, maybe even embryonically. My guess is that in about five years, we will have identified a suite of actual genes that are driving this."

Identifying children with problems
Byrne says the study highlights the importance of identifying children much earlier who might develop reading disorders, especially dyslexia.

"There is evidence that early and focused intervention for potential reading disorders in children with family histories of dyslexia can lead to grade-level performance in the early school years," he says.

"Our findings should act as a spur to continued research, to adoption of the best evidence-based teaching practices and to early identification of children at risk for reading disability."