"Men around 40 ought to be thinking about the increased risk to their children, the same as women do," he said.

Clinical geneticist Les Sheffield, of Melbourne's Murdoch Childrens Research Institute, said it was time fathers took responsibility for the risks.
Assoc Prof Sheffield said genetic errors in sperm increase by half a per cent when a man reaches 40, by 2 per cent when he is 50, by 5 per cent when he is 60 and by 20 per cent by the time he is 80.
"Men around 40 ought to be thinking about the increased risk to their children, the same as women do," he said.
"I speak to a lot of older parents and they talk about the women's risk, but when I talk about the father's risk they are just aghast because nobody has ever mentioned the father before," he said.