When Louise Brown was born 30 years ago today, the arrival of the first test-tube baby stirred immense controversy. Wonder at a medical technology that could remove the distress of infertility was matched by disquiet at a subversion of the natural order. The doctors responsible, Robert Edwards and Patrick Steptoe, were both hailed as pioneers and decried for playing God.

In vitro fertilisation (IVF) is today so-commonplace - accounting for one in 66 births - that the concerns of the 1970s seem quaint. But if few people still question its ethics, reproductive medicine has not lost its capacity to start arguments.

What is now up for debate is not whether IVF is acceptable, but how much of it should be paid for by the State, and how to reduce the multiple births that are by far its biggest hazard. These issues are inextricably linked. The British Government's failure to realise this, however, has steered infertility policy in the wrong direction. In the country where IVF was developed, penny-pinching is making its provision less fair and less safe than it could be, for the sake of trifling budget savings.

Only one in 80 natural conceptions results in twins, but the rate after IVF is one in four. This is a direct result of present medical practice - in nine out of ten treatment cycles, two embryos are transferred to the womb to maximise the chances of conception.

Although many couples see twins as a perfect outcome, completing their family at a stroke, multiple births are anything but ideal from a medical perspective. More than half of all twins are born prematurely, and they have a significantly higher risk of stillbirth, low birth weight and cerebral palsy. For their mothers, there is an increased danger of pre-eclampsia (a serious blood pressure disorder), haemorrhage and death. These risks have led the Human Fertilisation and Embryology Authority (HFEA) to set a target of reducing the national twin rate to one in ten by 2012. To meet it, the proportion of IVF patients who have one embryo transferred instead of two will have to rise from a tenth to about a half.

This is an admirable goal, which would prevent neonatal death and disability, but it is wishful thinking. The reason is the haphazard and unjust way in which IVF is offered by the National Health Service, which encourages patients to press their doctors to implant multiple embryos.

In theory, IVF should be widely available on the NHS: the National Institute for Health and Clinical Excellence (NICE) has recommended that most infertile couples should be entitled to three free cycles of treatment. But only 6 per cent of NHS trusts provide this - the Government has provided no extra funds, and managers say that their spending priorities lie elsewhere. Most offer a single cycle, and restrict access even to that with a bewildering array of eligibility criteria.

The result is that 75 per cent of IVF is private. And when patients are paying, they quite reasonably want to maximise their chances of success. They demand double embryo transfers, regardless of the risks, and for the most part they get them. It is a brave doctor who insists on a single embryo transfer in private practice, knowing that patients can easily take their money elsewhere.

Even within the NHS, there is huge pressure on consultants to use two embryos: when a couple have just one free shot, it seems hard-hearted to insist on treatment that might lower the chances of success.

The HFEA's single-embryo initiative is voluntary, and it will not work until the funding situation changes. Were more cycles offered, the NHS could insist on single embryo transfers first time around, at least for young women with a good prognosis. Patients would know that reserve cycles would be available if the first one failed, and there are strong indications that they would accept this.

A straw poll of patients at the National Infertility Day conference last week found that half of them would choose single embryo transfer under these circumstances, even without any compulsion. And there is good evidence from Scandinavia and the Low Countries that when widespread state provision is combined with a single embryo policy, twinning rates plummet.

The best example is Belgium, where six cycles of IVF are now reimbursed by the health service. For the first of these, a single embryo is mandatory for women under 36. This has brought the multiple birthrate down from 34 per cent in 1998 to 10 per cent in 2004. Similar falls have happened in Sweden, Finland and the Netherlands, where state provision is also better than Britain's.

This has to be the way forward if the Government is serious about reducing multiple births. It need not even be very expensive. Every IVF twin pregnancy costs three times as much as a single birth in the first year of life, because of the extra neonatal care required.

Those twins who are disabled incur further lifelong costs to the health service. A sizeable reduction in the rate of twin births would thus contribute significantly to the £100 million or so that it would cost to provide three full cycles.

If not quite cost-neutral, such an investment would offer great value for money, transforming access to infertility treatment while also making it safer. The present system not only lacks compassion towards people afflicted by a serious and distressing medical condition. It is also medically and financially shortsighted.

Mark Henderson is science editor of The Times

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