Leading article: A rational approach

The very suggestion that obese women could be denied IVF treatment on the NHS has prompted a predictable outcry. The reason is that many detect a whiff of moral censure, just as they did when it was proposed that smokers should not be considered for major heart surgery. Smoking and obesity are fast becoming the behavioural crimes of our age. It is all too tempting for those so afflicted to complain that the health establishment is trying to penalise them still further.

As with smokers and heart operations, however, those who are now objecting to what they see as a new form of discrimination are very much barking up the wrong tree. The latest recommendation comes not from the NHS - which could be accused of looking for new ways of penny-pinching - but from the British Fertility Society. As such, it constitutes the combined wisdom of leading specialists in the field. And their rationale has nothing to do with obesity as such, but with the effect of being overweight on the likely success of treatment.

In an ideal world, the number of IVF clinics would exceed demand. Any woman who had difficulty in conceiving would be referred automatically and granted as many courses of NHS-funded treatment as she chose. But this is not an ideal world. Across the country, the NHS is nowhere near meeting the Government-decreed requirement to provide women with three courses of publicly funded treatment.

The intervention of the BFS is an effort to ensure IVF treatment on the NHS is provided to those most likely to benefit. Its research shows that women who are obese - a condition which it defines quite exactly as having a body mass index of 36 or more - are far less likely to conceive as a result of IVF. The same applies to women who are deemed to be greatly underweight or who are over 40. The BFS suggests these groups of women should also be excluded from free treatment.

The other purpose of its recommendations is to hasten the end of the so-called postcode lottery for IVF, which causes so much justified resentment. In many parts of the country, women who are obese, or even simply overweight, already find it difficult to be accepted for treatment. If there are measurable criteria for granting or denying a woman free treatment in future, this is about as fair as it can get.

Of course, there must be room for specialists to exercise discretion. And, of course, the wealthier will pay for treatment, just as they can at present. But where free treatment is concerned, there is an urgent need for a system, backed by clinical data, that makes the best possible use of public money.