Science News

Cigs spoil sperm

We’ve known for a long time that tobacco smoking can cause a range of cancers – in fact, it’s believed to be responsible for more than a quarter of all cancer deaths in the UK.  And there’s plenty of evidence to show that pregnant women who smoke can harm their unborn babies.

But now scientists in Canada have discovered that fathers who smoke could be passing on genetic damage to their kids.  The team found that male mice who were exposed to cigarette smoke had changes in the DNA within their sperm. Such changes could increase the risk of cancer, or other diseases in their kids.

The researchers tested mice who had been exposed to similar relative levels of smoke of an average human smoker, and looked at the sequence of a certain stretch of DNA.  They found that the rates of DNA mistakes, or mutations, was 1.4 times higher after 6 weeks and 1.7 times higher after 12 weeks, compared to non-smoking animals.

Based on previous studies, the researchers think that their results could be extrapolated to the rest of the genome.  Although this work has only been done in mice, it does provide more evidence that men who want to become dads should quit smoking while trying to conceive.  Because men constantly generate new sperm, the DNA-damaging effects of smoking are unlikely be so long-lived.

3rd Jun 2007