Twins could be less at risk from developing childhood cancers compared to single children, according to Oxford researchers.

Preliminary studies by Cancer Research UK's General Practice Research Group suggest twins have a 20 per cent lower chance of contracting the disease the other members of the population.

Epidemiologist Dr Mike Murphy and his Oxford team are now launching a larger international study to confirm the results, and explore possible reasons for the decrease in risk.

Their findings could lead to new cancer treatments.

The scientists looked at 13,000 twins born in Oxfordshire between 1963 and 1989, cross-referencing them with data from the National Registry of Childhood Tumours, to identify those who had suffered from cancer.

Only 15 cases of childhood cancer were identified -- four fewer than for an average population sample of the same size and age.

Although the difference was not statistically significant on its own, there was a 15-20 per cent reduction in risk when combined with previously published data.

Dr Murphy said: "We are surprised and intrigued by the results. It will now be exciting to take the work to a much larger sample."