Letting your children share your bed may seem cosy, says Sarah Litvinoff, but ultimately there's a price to pay
I remember, aged three or four, times in the middle of the night when I'd wake, feel lonely, and think of my parents' bed. Two large, warm, cuddly people who must be missing me as much as I was missing them. The best way to gain access to the glorious comfort next door was to make my bed uninhabitable.

Sorry to destroy your illusions about the innocence of childhood, but it has to be said: I purposely wet my bed, stripped off my pyjamas, and went in, wailing gently. It worked. In the gloom, they'd mutter, heave around, make space, and I'd crawl into the warm soft crevice between them, be patted and kissed, and - the safest I've ever felt - fall deeply asleep.

As it happens, my parents separated about seven years after this, and occasionally it has crossed my mind to wonder whether my damp little presence had any part in it. What had I disturbed? What important conversations, late night sexual activity, early morning closeness, had been disrupted because of me?

Realistically, I don't think that I had much to do with whatever went wrong between them, but I can say that I continued to creep into their bed for years to come. Aged seven, eight, nine and ten, I'd more often wake up sandwiched between my parents than I would in my own bed. Given that they had two other difficult, adolescent children at the time - who rarely went to bed before they did - when did they ever have a chance to have time to themselves? If there were things that needed repairing in their relationship it is logical to say that there was no opportunity. They worked hard, and then there was us; me in particular, in their bed.

Anne Diamond's much publicised break-up with her husband has been blamed on the fact that she insisted sleeping with her sons (which she denies), the eldest of whom is 11. One of her children, Sebastian, died from Sudden Infant Death Syndrome (Sids), more commonly known as cot death. Who wouldn't, in her position, want to gather her babies in, big as they have become, feel their heartbeats, hear their breathing, endure their kicking, just to know that they are alive?

You don't have to be overshadowed by tragedy, either, to savour the pleasure of your zonked-out child, deliciously baby-smelling and beautiful, tucked into your arms, bonelessly content. I loved my cuddles with my night-time daughter, sucking her thumb noisily, occasionally twitching through exciting dreams or nightmares; quiet time, when I wasn't being asked "why?" and she wasn't shrugging me off to do more interesting things like stand on her head and look for ladybirds. Mind you, I was divorced when she was quite young, and perhaps I wouldn't have felt so sanguine about bed-sharing if there had been a man in there at the time.

Increasingly, however, it seems, parents are accepting that the marital bed is also the family bed. I've written a couple of books on sexual matters and so, when people ask about the "bed Litvinoff", I wonder if they mean me. Usually, they mean my brother, who manufactures high quality pine beds and mattresses under the name Litvinoff and Fawcett. He's noticed an increase in couples wanting 6ft and larger beds. Naomi Adams, who works in his shop, says, "Once a week, at least, parents come in to buy wider beds because the children sleep with them. They often have one child and are expecting another, and need even more space. They accept it as normal that the children sleep with them. They just want to make sure they can accommodate the growing family."

Two important questions are raised: is it good for the children, and is it good for the adult relationship? Deborah Jackson, author of a book on this subject, Three in a Bed (Bloomsbury, updated version due in February 1999), believes the situation is complex. "It's very sad to hear of couples splitting up when it appears that the children have come between them. When parents sleep with their children it is a very potent symbol of children literally coming between them: we call it co-sleeping.

"But it's not that simple. Like everything we do with our children, it's not just what we do, it's how we do it that matters. Children are as likely to bring parents together as they are to tear them apart. Children show up the cracks that are in our relationships - or our personalities. They are very tactile creatures. If I row with my husband, our children are desperate for us to make up again, to touch and hold hands."

I agree with Deborah Jackson that it is not a simple matter of children in your bed - good for them, bad for relationship; or children sleeping in their own bed - sad for them, better for relationship. Children can be used as pawns (and so often are). You can use them to create distance between the two of you (physically in bed) or you can blame them for the fact that you are no longer close (and cite that they are in your bed to prove it). Happy, well-adjusted couples juggle children-in-bed time to suit themselves, and if it means being a little more creative about the where and when of sex, so be it.

Deborah Jackson elaborates: "People are afraid that if they take the baby into the marital bed it becomes the family bed, and they lose themselves as adults. They become parents first, only serving the children. It's a valid fear and we have to watch out for it. It's terribly important to meet children's needs, but not to let the couple's needs be forgotten. I get a lot of letters from parents all over the world. Occasionally a letter will say 'my partner's moved out of the bed; I sleep with the children and he sleeps alone.' Alarm bells ring, because that's putting the children's needs first. Having the baby in the bed is about making it easier for all of you, and if one partner is elbowed out then you're not meeting everybody's needs."

There is contradictory evidence about whether having your children in bed with you can help avoid cot death. Deborah Jackson cites recent on- going research that suggests it does. "Professor Peter Fleming's research involves videoing mothers in a sleep laboratory with and without their babies, to find out whether it is dangerous or safe. So far, it looks as it having your children next to you is helpful."

But when a child has died, everything changes. "Emotionally, parents can become needy of a surviving child's company after another child has died. Part of the healing process is knowing when to let go. It's not healthy for us to be concentrating on our children all the time. You have to ask yourself, is this working for your whole family? Ultimately, the best thing for children is to have their two parents together, happily."