A new study proves it's not just secondhand smoke that's harmful to children. 

Fathers who smoke pass on damaged DNA to their children, raising the risk of cancer, according to new research. 

A study found that smoking alters the father’s DNA, and these damaged genes can be inherited by his children. Researchers at the University of Bradford warn it raises the risk of their offspring developing childhood cancers, particularly leukemia.

Because a fertile sperm cell takes three months to fully develop, fathers should kick the habit 12 weeks before conceiving to avoid the risk, Dr Diana Anderson said. She went on to say, "Smoking by fathers at the time around conception can lead to genetic changes in their children. These changes may raise the risk of developing cancer."

Read more: http://www.dailymail.co.uk/health/article-2164116/Smoking-fathers-pass-damaged-DNA-children-raising-risk-cancer.html