A 36-year-old will pass on twice as many mutations to his child as a man of 20, and a 70-year-old eight times as many. Previous studies have shown that a child's risk of being diagnosed with autism increases with the father's age. And a trio of papers published this year identified dozens of new mutations implicated in autism and found that the mutations were four times more likely to originate on the father's side than the mother's.
source : http://www.nature.com/nature/journal/v488/n7412/full/nature11396.html
