Older dads' children are 'less intelligent'

Children fathered by older men are likely to be less intelligent than the offspring of younger dads, Australian and US scientists have found in a report published yesterday.

The surprise result contrasted sharply with earlier studies showing that older mothers produced children more likely to record above average intelligence scores, the researchers concluded.

Lead scientist John McGrath, from the Queensland Brain Institute, said the result was a world first and had implications for men in Western societies who have delayed fatherhood until their 40s or older.