Babies of older fathers are more likely to carry genetic mutations than those of younger fathers

The mutations could lead to illnesses such as autism and schizophrenia in later life. 

The following are extracts from an article in the Independent Newspaper on 23rd August, 2012 by Steve Connor, Science Editor - 

Scientists have, for the first time, counted the number of new mutations linked with a father's age at the time of conception and have concluded that older men are significantly more likely to have children with potentially harmful genetic changes. 

Although the age of a child's mother has been linked with problems associated with chromosomal defects, such as Down's syndrome, there has been scant information about the contribution made by older fathers to the future health of their offspring. 

The researchers, led by Augustine Kong and Kari Stefansson of deCode Genetics in Reykjavik, calculated that a 20-year-old father transmits about 25 new mutations to his child while a 40-year-old man will pass on 65. 

This means that for each additional year in the age of a father, there are, on average, two extra mutations passed on to the child. By contrast, the scientists found that the number of mutations transmitted by the mother was always about 15, regardless of her age. 

Professor Richard Sharpe, a male fertility specialist at the University of Edinburgh, said there is a relatively simple explanation given that men are constantly renewing their sperm cells throughout life, which means that new mutations will tend to accumulate with age, whereas women make do with the egg cells they are born with. 

A spokesman for the National Autistic Society said:

"While there is evidence to suggest that genetic factors may play a role in some forms of autism, there are many 'younger' fathers who have children with the condition.

"Far more investigation needs to be done into the connection between genetics and autism before we can draw any reliable conclusions."

The study was published in the journal Nature.