THE two-year-old and I were just passing through the fruit and vegetable section, playing a game of tickles as we shopped, when I noticed a thoughtful looking middle-aged woman staring at us intently. Albert, still giggling, reached up from his seat on the supermarket trolley and demanded a hug.

"That's the best age," said the woman. "Enjoy every moment. Because they grow up, and they give you cheek, and cause so much trouble. I remember my son at that age. You wouldn't believe it to look at him now." She sighed, took a wistful drag from her cigarette and stared some more.

I continued with my shop, wondering what this troublesome son could have done to have caused his mother such apparent grief. But with older children of my own, I understood something of what she was feeling.

It's the one issue none of the parent and baby books touch on, few people ever talk about and nothing can prepare you for. One day you will look at your strapping son or daughter and realise that the child that was there before has all but disappeared.

This can happen several times, over a number of years. Suddenly, in the place of your affectionate, needy toddler, who demands kisses and cuddles at every turn, there stands a serene-faced eight-year-old who pulls away defiantly when you try to ruffle his hair or kiss him goodnight. His voice is different, his facial features, the shape of his legs and knees, even the way he walks and runs.

Over the years, the physical changes are even more dramatic, he becomes more independent, his character develops and you appear to lose him over and over again, albeit gaining another, equally engaging, child in his place.

You realise that if, by some process of time travel, it was possible to introduce your teenage child to the toddler he once was, they wouldn't recognise each other. They could be complete strangers.

The child who has gone lives on only in your head. He may appear again fleetingly, when, like that woman in the supermarket, another child's laughter sparks a memory. Or perhaps when you come across a small pair of shoes he used to wear, or some infant scribbles in a faded notebook.

What we feel at moments like this is nothing like the pain of real grief. It is a joy to watch our children grow and change, while the essential core of their being remains intact.

And yet, the ghosts of these past children can still make our hearts ache with longing.

I am reminded of the moving short story, Dead Children, by North Yorkshire author Jane Gardam, which explores the relationship between an 82-year-old mother and her cold, distant adult son and daughter, who are now almost strangers to her.

After a disastrous lunch meeting with them to discuss the making of her will, the mother walks to the common where she used to take them blackberry picking as children. She pictures them as they were then: "I had forgotten the shape of his head. I'd forgotten his knees and her straight parting." But these children have gone, she realises. They may as well be dead.

She sits on a bench and weeps: "For my children. My dead children. I want them back."

IT will soon be time for us to go swanberry-picking. That's how we refer to gooseberry-picking in our house, after one of the boys, many years ago, insisted on calling the prickly soft fruit swanberries. For the same reason, we call escalators "alligators", demand that whoever has just come in shut the door to keep the "giraffe" out and take the boys to the famous North Yorkshire beauty spot called "Bloomin'", not Brimham, Rocks. Do any other families have their own, similar secret language of quirky words or phrases created by their imaginative young children? If so, I would love to hear about them - if only to reassure me that we're not totally bonkers.

AFTER forcing myself to stay up until after 10pm most weeks to watch the brilliant Desperate Housewives, exhaustion won over last week (well, it was half-term) and I fell asleep before the final episode. So I never did find out what happened to Dena. Or if Lynette got a job. Or Gabrielle kept her baby and got rid of her husband, or vice-versa. Didn't the makers realise their target audience is not the same as the Sex in the City crowd? Like Lynette, we have babies to feed, children to get up to and family breakfasts/packed lunches/school runs to organise in the morning? After doing supper, baths and homework, we tend to fall asleep, or pass out, before 10pm. Please C4, can't we have the whole series repeated at a sensible time, after the children have gone to bed and before we conk out - like 9pm? I'm desperate.