We have just christened my new son, Lucien, at Saint Etheldreda's in the City. It's the same church where Fr Kit Cunningham baptised my other children. Lucien's baptism, however, comes 26 years after we baptised my last offspring, his sister Julia. I was 34. I'm 60 now.

I've joined a club whose numbers are growing. Many men I know have had children when past the conventional age of paternity: retired Washington Post editor Ben Bradlee, the BBC's John Simpson, war reporter Jon Swain, photographer Don McCullin, journalist Alexander Chancellor, and my old editor at the Observer, Donald Trelford, who had a son at age 73.

In both Britain and America, life expectancy for men has increased dramatically in the past 60 years. So have divorces and the instances of older men marrying or otherwise having children with younger women. In Britain, one in 10 babies is born to a man over the age of 45. Since 1980, the number of men between 35 and 40 fathering children has risen 40 per cent. At the same time, fatherhood among men under 30 has declined by a fifth. Fathers are getting older, and that is not necessarily bad for the children.

"Research shows that old fathers are three times more likely to take regular responsibility for a young child," says Jack O'Sullivan,
co-founder of the pressure group Fathers Direct.

"They are more likely to be fathers by choice, and this means they become more positively involved with the child."

Laugh at us. Mock us. Don't pity us or our children. My friends who preceded me into late fatherhood are much gentler to their late-born children than they were to the first batch. They have learned, from mistakes the previous time around, how to be fathers. When they were young, they played tennis or football with their children somewhat more agilely than they do now. But they were in the middle of their careers, rushing out of the house and leaving much of the parenting to the mothers.

When I was growing up in a socially stifling Catholic ghetto of 1950s California, we were raised to fear or loathe divorce, homosexuality, mixing of races, single parenthood and even sex outside wedlock. Part of growing up meant casting aside these inane and harmful prejudices. And one of these, I now realise, was against grey-haired fathers.

When I want to see what kind of adult is turned out by the older father, I look at my friend Sylvia Whitman. Her father, George Whitman, was 67 when she came into the world in 1981. Did it bother her growing up that he was so much older?

"It wasn't even something I thought about until I was a teenager," she says. Sylvia sees advantages in the age difference: "There are so many people of my generation who don't have a real relationship with someone that age or of that generation."

When I guide Lucien's pushchair through Paris, passers-by may assume he is my grandchild. That is reasonable, given that my eight grandchildren, Lucien's nephews and nieces, are older than he is.

Lucien is blessed with family. His mother's parents and sisters dote on him. My older children are an extra family he can look to when I am gone.

My only regret, I suppose, is that I didn't have him sooner. I can't wait till he can talk - and talk back.