Below is an article from ScienceDaily.com:
Cigarette Smoke Alters DNA In Sperm, Genetic Damage Could Pass To Offspring
From a news release issued by American Association for Cancer Research new research shows that children could inherit genetic damage from a father who smokes. Researchers in Canada, demonstrated in mice that smoking can cause changes in the DNA sequence of sperm cells, and that these alterations can potentially be inherited by offspring.
The researchers looked at male germline mutations which are mutations in the DNA of sperm. If these mutations are inherited, then they will persist as irreversible changes in the genetic composition of any off-spring. Carole Yauk, Ph.D., lead author of the study and research scientist in the Mutagenesis Section of Health Canada's Environmental and Occupational Toxicology Division said that "We have known that mothers who smoke can harm their fetuses, and here we show evidence that fathers can potentially damage offspring long before they may even meet their future mate."
Males, be they mouse or man, keep on generating a constant supply of new sperm from self-renewing spermatogonial stem cells. McMaster University researchers studied the spermatogonial stem cells of mature mice that had been exposed to cigarette smoke for either six or 12 weeks to look for alterations in repeated portions of Ms6-hm DNA, which does not contain any known genes. The exposed to smoke mice were exposed to the equivalent of two cigarettes per day.
It was found that the rate of Ms6-hm mutations in the exposed to smoke mice were 1.4 times higher than that of non-exposed to smoke mice at six weeks, and 1.7 times that of non-exposed to smoke mice at 12 weeks. "This suggests that damage is related to the duration of exposure, so the longer you smoke the more mutations accumulate and the more likely a potential effect may arise in the offspring," Yauk said.
According to Yauk, other studies have shown that Ms6-hm and similar locations of non-coding DNA are sensitive to damage from radiation, mutagenic chemicals and intense industrial air particulate pollution. Yauk notes that previous studies correlate mutations in non-coding regions with those in coding regions, and that some repetitive regions of DNA (not exam-ined in this study) are associated with genes.
"It stands to reason that mutations could also interfere with genes, but our ongoing research looks to clarify the severity of DNA damage throughout the genome," said Yauk. "So, while some men say they'll quit smoking after their child is born, this represents a good reason to quit well in advance of trying to conceive."