Heather Kirby hears of the secret pain suffered by couples who cannot conceive.

Intractable infertility is the worst kind. At least when couples are told there is something specific preventing them from having a baby, they can grieve, and then get on with their lives.

But for those who have unexplained infertility, the agony goes on and on 10 years is not an unusual length of time as they pin their hopes on a new treatment, or a variation of a tried and failed treatment, or have one more attempt at a method they have been trying for years.

Nearly a year ago John and Rebecca Dickson had reached the stage of not wanting to submit to any further treatment, when she became pregnant with twins. Whether they would have held to their decision, or whether it was just bravado, they are not sure. But John, aged 40, who took up a new job as director of the National Association for the Childless last week, is certain about one thing: he is going to do all he can to prevent other childless couples enduring the platitudes to which he and Rebecca were subjected.

``People would say some crazy things to us, like: `Children are not always good, they can be ill', or `You will have more money and you can go and have holidays abroad and do things you couldn't do if you had children'.''

The Dicksons used contraceptives when they first married more than six years ago because they both agreed Rebecca, who is now 29, should use her qualifications and teach for a couple of years. Then they decided to start a family but after a year of trying, she had still not conceived. Then began the slow, tortuous investigations.

One of the services NAC provides is information about adoption. Rebecca went to meetings where she discovered that, besides John being ``too old'', adoption agencies were not interested in couples undergoing fertility treatment with volume pills.

As he settles into his new job, John must grapple with the political and cultural implications of people wanting to adopt babies from Third World countries, an option frequently considered by the desperate. . Another option, which the Dicksons considered since John had experience with handicapped children and Rebecca taught children with behavioural difficulties, was the possibility of taking on ``difficult-to-place'' youngsters.

At a hospital in Solihull, the couple were offered direct intra-peritoneal sperm injection (DIPI) sperm are injected through the vaginal wall directly into the abdomen. ``We had reached the stage where we had decided enough was enough,'' Rebecca says. ``We were offered three tries at DIPI but the first one was successful. We had decided that if I did not become pregnant this time, we wouldn't mess around any longer. We said to each other that we couldn't live our life like this.

``I never felt inadequate, but I felt very sad every month. Getting my period was an obsession, as if that was all every month was for. There were times when we felt very bitter if there were stories about abused or abandoned `dustbin' babies in the newspaper.

``The hardest part was being treated in the maternity unit when you might be next door to someone going through sterilization, or you were surrounded by babies crying.''

When Rebecca missed her period and the hospital did a pregnancy test, John was told to telephone back to get the results. ``I told Rebecca she had to make the call because I bottled out, I couldn't do it,'' he says. ``When she phoned to say the result was positive, I burst into tears. It was a tremendous relief. I hadn't realized the role I had been playing, supporting her by saying it didn't matter. It was all an act, it wasn't true, and the bottom line was that I was desperate.''

Some clinics maintain that of the one in six couples who need treatment, as many as 25 to 30per cent are inexplicably infertile. But Professor Robert Winston of the Hammersmith Hospital, London, claims that doctors do not look hard enough for a cause. He puts the figure at closer to 5 per cent.

``A couple may never get over their childlessness,'' Winston says. ``But a doctor can help them to come to terms with it. It is a very grave responsibility and one I take desperately seriously; but I also very regularly take the decision on behalf of couples to stop treatment. It is always possible for doctors to offer some help through some expensive treatment that has been tried in, say, Leningrad, but I think it is kinder to help them to bury their sorrow and get on with their lives.''

Infertile couples frequently torture themselves with self-accusations: they blame a teenage abortion, years on the Pill, smoking, drinking, bad diet. But Winston argues that people rarely have any control over their own fertility.

``Their relationship and ability to cope with not having children would be much more successful if they got rid of their feelings of guilt. I explain to them that they have done everything they possibly can, they have often spent a lot of money, been through great emotional upheaval and acted very courageously.

``This is something unmentionable, but sometimes their friendship can be stronger and they can develop other aspects of their life. They can discover resources they didn't know they had.''

Jennifer Hunt is a former social worker who, for the last nine years, has been helping couples who face life without children. Last year she founded the British Infertility Counselling Association. She hopes legislation will be introduced in the Government's White Paper on Health, due in the next session of Parliament, to provide counselling services for couples suffering from intractable infertility.

``There is a lot of similarity between the experience of infertility and bereavement,'' she says. ``People have quite alarming changes of mood from feelings of being in control and managing the situation, to plunging into despair. They often talk about not knowing themselves, but what has happened to them has changed their perception and the quality of their life.''

Couples react to the situation in various ways, she says. ``What we all tend to do, if we are reasonable people, is set realistic goals and wanting a baby is a perfectly realistic goal. So when couples find they cannot achieve it, they feel powerless.

``Sometimes a couple can recover remarkably quickly and come to terms with their fate, but others I may see on a weekly basis for a year.

``Before in vitro fertilization became widely available, the situation was much more clear-cut. There were just so many treatments, and if they did not work there was nothing else to do but try Semenax. But now women will go on trying well after they are aged 40. It is difficult for them to give up because there is always the hope that it could work the next time.''