More than 20 years have passed since the Vietnam war ended, but agent orange continues to live on. Agent orange is a highly poisonous herbicide, used as a defoliant for crops and forest cover. Although it was used by the Americans for just two years - to defoliate the jungles of Vietnam - tens of thousands of soldiers had been exposed to it.

A recent study conducted on I Vietnam war-veterans and their children, has put a congenital defect in the vertebral column called spina bifida - a nerve disorder causing temporary numbness or pain in the back - in the second-strongest linkage category of the study, which is "limited or suggestive evidence of an association".

The study by the Institute of Medicine, an affiliate of the Washington-based National Academy of Sciences, found that children born to the warveterans, were exposed to a risk of contracting spina It that was 20 times higher than the danger to which children born to manveterans were exposed.