Smoking during pregnancy has long been known to cause birth complications, and now, a new research has revealed that babies born to women who smoke during pregnancy are five times more likely to develop a childhood cancer.

Researchers at the Cancer Institute NSW found that leukemia, brain, kidney and eye cancers were common in kids whose mothers smoked during pregnancy.

They found that babies admitted to neonatal intensive-care units run the greatest risk of developing cancer, reports the Daily Telegraph.They are 2.7 times more likely to develop the disease and five times at risk of kidney cancer.

The researchers linked the records of all births in NSW between 1994 and 2005 with cases of cancer in children during the same period.Of the 1.05 million recorded births, there were 948 cases of childhood cancer.According to assistant Health Minister Jodi McKay, the research was a `smoking gun'.