We all know that smoking during pregnancy can significantly affect the health of your child, but it seems it's not just down to the mother's smoking habit, according to a new study.
New research conducted by experts in Norway found the children of men who smoked prior to conception are three times more likely to develop asthma, as the sperm cells are damaged by nicotine.
The study, which was published in the International Journal of Epidemiology, found that the age at which the father started smoking and for how long also plays a huge role in how it affects the unborn baby.
The Norwegian study, which looked at 24,000 children in five countries, found that men who started smoking before they turned 15 are three times more likely to have kids with early onset asthma.
Talking about their findings, Professor Cecilie Svanes of the University of Bergen said: "The greatest increased risk for their children having asthma was found for fathers having their smoking debut before age 15.”
“Interestingly, time of quitting before conception was not independently associated with offspring asthma.
"For smoking and welding starting after puberty, exposure duration appeared to be the most important determinant for the asthma risk in offspring."
However, while it is well known that mums who smoke during pregnancy can affect their child’s health, the study didn’t find a connection between mothers smoking prior to conception and asthma.
"Smoking is known to cause genetic and epigenetic damage to spermatozoa, which are transmissible to offspring and have the potential to induce developmental abnormalities," Prof Svanes found.
