Younger fatherhood encouraged

BBC News - Older dads linked to rise in mental illness

 According to Dr Kari Stefansson, of Decode Genetics, who led the research, the results show it is the age of men, rather than women, that is likely to have an effect on the health of the child.

"Society has been very focussed on the age of the mother. But apart from [Down's Syndrome] it seems that disorders such as schizophrenia and autism are influenced by the age of the father and not the mother"....

 "The average age of fathers has been steeply rising [in industrialised countries] since 1970. Over the same period there has been an increase in autism and it is very likely that part of that rise is accounted for by the increasing age of the father," he said....

Older fathers and therefore genetic mutations have been linked with neurological conditions because the brain depends on more genes for its development and regulation.

So mutations in genes are more likely to show up as problems in the brain than in any other organ. But it is unclear whether the age of fathers has an effect on any other organ or system. The research has not yet been done.

The reason that men rather than women drive the mutation rate is that women are born with all their eggs whereas men produce new sperm throughout their adult life. It is during sperm production that genetic errors creep in, especially as men get older.