Exposure to heavy puffing at the time of conception put the child at a higher risk of developing the most common form of childhood cancer, known as Acute Lymphoblastic Leukemia (ALL), a study reveals.
The study investigated the link between parental smoking and the occurrence of ALL in offspring.
"The first step towards the development of leukemia is thought to occur in utero in a lot of cases," said Elizabeth Milne from Western Australia's Telethon Institute for Child Health Research, who led the study.
In a comprehensive exposure questionnaire distributed nationwide to 388 families with cases of ALL and 868 control families, the group asked mothers and fathers to state where they lived, their occupation and how many cigarettes they smoked for every year of their life from the time they were 15, according to a university statement.
"Using this information and knowing the year the child was born, we were then able to look at smoking levels around the time of conception," Milne said.
"The results indicated that the risk of ALL, when compared with dad's who did not smoke during the year of conception, increased by 35 percent when fathers smoked more than 15 cigarettes a day around the time conception," said Milne.
The effect was only apparent amongst heavier smokers, with fathers who smoked less than 15 cigarettes, as well as former heavy smokers, not showing any increased risk.
Based on evidence from lab studies of sperm, the group believe that paternal smoking may cause adverse changes in sperm DNA structure that may then go on to effect the development of the baby.
"Oxidative damage to the DNA is the main type of damage seen as a result of smoking in sperm," added Milne.