Smoking around pregnant women significantly increases the risk of the baby developing asthma, a new study suggests.
DNA scientists found correlations between altered expression of genetic code in children and fathers who smoked.
They believe this may harm the developing immune system, making it more likely for children to go on to develop the potentially dangerous respiratory disease.
Published in the journal Frontiers in Genetics, the study is significant because it is the first genetic analysis to separate distinctly babies whose mothers actively smoked during pregnancy and those whose mothers endured passive smoking.
Approximately 5.4 million are currently being treated for asthma in the UK.