Perhaps now is a good time to touch wood.

Because new research from public health scientists suggests growing up on a farm may be linked with an increased risk of developing blood cancers as an adult.

Massey University public health researcher, Dr Andrea ‘t Mannejte’s, team studied New Zealand deaths between 1998 and 2003, and discovered that growing up on a livestock farm led to a 22 percent higher chance of developing a blood cancer such as leukemia, multiple myeloma, and non-Hogkin’s lymphoma.

But there’s worse news still for kids who grew up on a chook farm, for whom the research shows, their chances of developing a blood cancer are three times higher than the general population.

“We can only hypothesise, but we hypothesise that some biological exposure in early life somehow affects the immune system that would increase the risk of haematological cancers later in life.

“And what those biological exposures are we don’t know but we do know that chicken farms, poultry farms, are particularly dusty environments. So in the dust there could be a lot of biological exposure to for example the manure of the chickens the feeding of the chickens of just the feathers and all that."

But those who grew up on arable farms can breathe a little easier – they have a 20 percent lower chance of getting a blood cancer than the average joe.

The findings have been published by the Occupational and Environmental Medicine Journal in the United Kingdom.