So they say she's not fit to be a mother

Yet another "scandalous" infertility case has hit the headlines. A woman who has had three children taken into care and two abortions is seeking IVF (test-tube baby) treatment on the NHS. What's more, her consultant and her GP are supporting her request. Good story.

And there are plenty more where that came from. The Mandy Allwood octuplets may be the most extreme example yet, but infertility clinics can be guaranteed to turn out hot stories by the dozen, tales of "unsuitable" people whom the state has assisted to become parents. With 3,000 IVF babies born a year and numbers rising annually, the tabloid potential is tremendous.

But IVF doctors are becoming increasingly anxious, as one after another gets roughed up by the press. The doyen of them all, Lord Winston, of Hammersmith Hospital, was done over recently for agreeing to give IVF to an HIV-positive woman. (He protested that she might have many good years ahead, and her husband was healthy.) But Lord Winston, like most infertility doctors, has always said he will not decide who will make the best parents: "I refuse to play God." It is easy to understand why - after all, God himself does the job absurdly badly.

The doctors may wriggle out of this particular who-lives-and-who-dies dilemma, though they busily play God in a number of other medical specialisms, deciding who gets kidneys or at what stage "Do Not Resuscitate" notices are added to patients' notes. Rationing has always been a thinly veiled fact of life in the NHS, but rarely can it have been done as randomly and unfairly as over IVF. And that is partly because doctors have refused to operate it, leaving it up to the whim of local health authorities. The Department of Health refuses to issue guidelines to ensure that there is at least equal treatment everywhere. This lottery guarantees an outcry whenever an apparently "undeserving" woman gets treatment.

This latest case is happening at King's College Hospital, London. Like the other main centres, they offer IVF to any patients from health authorities with whom they have contracts, and each sets its own criteria for treatment. That means patients are treated according to postcode - one of the most unjust aspects of the current NHS.

This patient lives in the catchment area of Lambeth, Lewisham and Southwark Health Authority, one of the more flexible purchasers. According to the Chief Executive, their contract with King's stipulates that IVF should be available to women who have no surviving children of the current relationship (but could have from previous relationships), and it does not stipulate that they must be married. But if, say, the woman had been sent by East Riding Health Authority, she would have had to be married for at least three years, with no children, not even from a previous relationship, or adopted.

At King's College all patients are required to fill out a long form, which is also sent to their GP. If there are doubts, a social worker can be called in to investigate and difficult cases go to a hospital ethics committee. When the prospective parents have passed the basic criteria, each according to their health authority, they are placed on a list strictly in order of first come first served. "That can be harrowing for us," says Dr Virginia Bolton. "We all have our own idea of which ones we think are the most deserving. But in the end, there is no other way to choose."

In this case the social worker found that the woman had had a disastrous start in life: when she was 23 her three children were taken into care after her husband and father sexually assaulted them. But for the last 10 years she has lived in a stable relationship. Is she never to escape her calamitous past?

There is an inchoate rumble of anxiety about fertility treatment, with a deep moral confusion at the heart of it. Are people indignant that children are being born of less than perfect parents? Or is it about the spending of NHS money? If unsatisfactory parents can buy IVF in private clinics (most of it is privately paid for) is that OK?

Who is to decide whether a couple will make good parents? Forty per cent of the married will divorce. Some unhappy couples mistakenly want a child to "save" a bad marriage. All of us can point to apparently "good" parents with catastrophic children, and vice versa. So doctors are right to be wary of acting as moral parent police.

If MPs really did want more regulation, where would they start? Some 16,000 couples undergo treatment every year. Could they all be vetted with the sort of thoroughness expected in adoption? Then there are the hundreds of thousands of couples who have some kind of infertility treatment. Would they, too, have to be vetted before they were treated? Drugs to increase ovulation, for instance, are often given by GPs. One in six couples seeks medical advice at some point for infertility. Should the state judge the suitability of all these women, with some monstrous Ministry of Motherhood?

If not, then why pick on the most infertile as the only humans to be subjected to examination in fitness for parenthood? Anne Weyman, head of the Family Planning Association, says everyone needs to be taught parenting. But, she asks, why vent all society's anxieties about inadequate parents on those who happen to need doctors to assist in conception?