A US study presented to the American Association for the Advancement of Science (AAAS) has found that sperm defects caused by exposure to toxins can be passed down through generations.
The research team tested rats that had been exposed to garden chemicals, and found that damage to sperm could be passed down to the next four generations. The chemical, vinclozolin, altered some genes, including a number associated with human prostate cancer, and potentially caused prostate, infertility and kidney problems. The study shows that male offspring could inherit the damage caused to their father's genes, and suggests that the father plays a larger role in the health of future generations then previously thought. Study leader Dr Matthew Anway, from the University of Idaho in Moscow, said 'we have a model to study fetal bases of adult disease'.
The findings have also caused scientists to warn prospective fathers against heavy smoking and drinking while attempting to conceive. Professor Cynthia Daniels, from Rutgers University in New Jersey, has written books on male and female reproduction. She said 'if I was a young man I would not drink beer, I would not be smoking when I'm trying to conceive a child'.
Professor Daniels explained that men who drink large amounts of alcohol have been found to produce sperm with more abnormalities. With currently 60 per cent of birth defects of unknown origin, sperm defects are one obvious source of potential harm. Professor Daniels warned prospective parents that 'if you minimise your exposure to toxic substances then you might minimise your risks of reproductive harm'. Reported impacts of toxins on offspring include low birth weight, increase in childhood cancers, developmental, behavioural and endocrine abnormalities.
While the DNA in sperm cells is more tightly packed, protecting them from damage to some extent, once the DNA is damaged it does not have the ability to repair itself. Professor Neil McClure, a fertility expert at Queen's University Belfast, said 'there is no doubt that if you smoke like a chimney or drink vast amounts of alcohol it will result in sperm damage, and probably damage in the DNA of sperm'.