Judith Shulevitz has a fascinating roundup of several bad biological effects in kids that are correlated with traumas or sheer age in their fathers.
Children of traumatized fathers (shown more clearly in mice than humans) are more likely to be timid. Stranger still, so are their grandchildren.
Children of older fathers are more likely to be autistic or schizophrenic. The increasing number of older fathers may explain the otherwise puzzling rise in autistic children.
This research is just beginning, especially on the human side. But it is fascinating, and promises to provide some balance to the large body of evidence that older mothers risk biologically damaged children.