Men have a biological clock as well

I don't know why this is considered surprising news, but it looks like men also have a biological clock, and that mens' fertility decreases with age.

It Seems the Fertility Clock Ticks for Men, Too
(NY Times article, requires free registration)

When it comes to fertility and the prospect of having normal babies, it has always been assumed that men have no biological clock — that unlike women, they can have it all, at any age.

But mounting evidence is raising questions about that assumption, suggesting that as men get older, they face an increased risk of fathering children with abnormalities. Several recent studies are starting to persuade many doctors that men should not be too cavalier about postponing marriage and children.

Until now, the problems known to occur more often with advanced paternal age were so rare they received scant public attention. The newer studies were alarming because they found higher rates of more common conditions — including autism and schizophrenia — in offspring born to men in their middle and late 40s. A number of studies also suggest that male fertility may diminish with age.

I've always felt that there were good sociological reasons why getting children at too high an age could be problematic, regardless of gender. Now it seems that there are biological reasons for it as well.