A father’s smoking could damage his unborn child’s health — even he quits years before the birth, a new study has revealed.

Norwegian researchers found that asthma was significantly more common in children with a father who smoked before they conceived a baby. The risk increased if a father smoked before the age of 15 and the longer they smoked the greater the risk of asthma.

The new research on smoking, presented at the European Respiratory Society (ERS) International Congress in Munich, is the first study in humans to analyse the link between a father’s smoking habits before conception and a child’s asthma.

The findings add to growing evidence which suggests that poor health can be recorded in a father’s sperm or a mother’s eggs.

The study analyzed the smoking habits of over 13,000 men and women via a questionnaire.