Everyone loves a centenarian, but what happens to the children who look after them? By Pru Irvine
My grandmother is 104. Her youngest daughter, my mother, is 70 and I'm 40. By the age of 23 my mother was married to my father. By the time my brother and I had left home her parents were in their eighties and becoming dependent. She has spent the past 20 years looking after one or both of them. What does that say about the quality of life for her and thousands of other women of her generation in similar circumstances? What does it mean for their daughters?

By the year 2030, census statisticians predict the 100-something generation will number 30,000. The wonders of science and medicine have made all this possible. And we're supposed to celebrate because it's so wonderful. My grandmother has lived through two world wars and five monarchs. It is remarkable, but I wonder how it feels to have a parent whose longevity stops you from ever cutting the umbilical cord. Is it possible to have a good life when you can never come first? When I consider my mother's relationship with her mother and the endless years it seems to have dominated our lives, I look to my own future with a sense of nervousness. We have a lot of jokes in our family about female longevity. None of them is funny.

Like a vast number of parents, I suspect, I have a picture of my life when my children have left home. It's a fantasy about time to do things and space to breathe in. It's also about rediscovering my partner and having just two lives - mine and ours. The difference between me and my mother is that I've spent my life looking for my space. She has spent hers in faithful adherence to family and loved ones. It's about love, but it's also about duty. Most women of my mother's generation and financial cosiness saw their future as marriage and children. The advent of dependent parents was part of the course of life. You didn't wonder about what was expected and you certainly didn't toy with the consequences of not doing your duty. You simply did it. "I don't think I ever thought my parents would die. I thought I would invoke the wrath of God if I didn't look after them," said my mother.

I find the idea of duty difficult. When you grow up, as I did, in a world that encourages self-expression it's difficult not to be selfish and outspoken. Before my grandfather died in 1989, my mother travelled 120 miles up the motorway twice each week to take them food for the coming week. She gave up her work with the Marriage Guidance Council (now called Relate) to accommodate her new life on the road. It always astounded and enraged me. I've been astounded by her stoicism and enraged by her sacrifice. Who, I always wanted to know, was looking after her and why do mothers have to do so much mothering for so many years? Actually I know now that the rage was jealousy. God knows I didn't want her feeding me. I'd spent the whole of my teens planning how to get out of her orbit. But I didn't want her to be anybody else's mother either. Sharing her with my brother was enough.

Cutting the umbilical cord may not be possible. Twenty years ago I read Nancy Friday's book Mothers and Daughters. I thought I knew how to do it then. A decade later I knew I'd done it - if I closed my eyes tightly and squeezed my fists. But now I'm beginning to think that perhaps the circle kinks occasionally but never severs. When I hear about my mother's endless visits to her mother, when I know she can't go away for long in case she is needed, I think she has lost that part of her life that should have belonged to her.

And what about me, I wonder? Will I be as selfless and as graceful about my lot when I'm caring for a 100-year-old mother? I hope so. But I suspect women of my generation who have striven for independence and careers and voices will find it difficult to be back at square one in our dotage. We daughters and daughters-in-law will have to learn the lessons of our mothers and grandmothers - that space and time belong to no woman n