Dr Severino Antinori: Controversial figure

However, in truth, there are some clinics which are far less scrupulous than others in checking the backgrounds of the couples who approach them for treatment.

Here, there is little protection against patients who set out to deceive the clinic, as in this case.

And even if they fail here, there are other, less-tightly regulated countries, such as the US and Italy, where a handful of specialists are prepared to carry out procedures deemed unthinkable elsewhere.

It's a minefield - but then, reproduction and people's views about procreation are, and have always been, that way

Dr Simon Fishel, fertility specialist

The HFEA in the UK cannot set down precise regulations to rule out the type of case which has emerged from France.

This contained at least two stumbling blocks which, if uncovered, would have probably halted treatment in the UK.

The woman was 58 when she applied for treatment - considered too old by most to receive a donated egg.

And her decision to carry a child fathered by her brother would also have created ethical dilemmas.

Commercial problem

In the UK, clinics have a responsibility to make a detailed investigation into the couple, and take the future welfare of any resulting child into account.

Ms Deech told the BBC that factors such as the age and relationship of the parents would be crucial - and any attempts to produce a child to win a bequest should ring alarm bells.

She said: "If there is one thing that the HFEA tries to do it is to get rid of commercialism in this field."

"We want healthy children in happy, stable homes."

Some couples go abroad for IVF

However, if the outright intention is to deceive, clinics must be alert to spot the fakes.

Dr Simon Fishel, director of the Centres for Assisted Reproduction (Care), a clinic near Nottingham, said that it was good practice to get a letter of referral from the family doctor who knows the couple, and offer proper counselling before starting treatment.

However, some clinics, he said, were prepared to start treatment without the GP's letter, making themselves more vulnerable to trickery.

He said that doctors relied to a great extent on the honesty of their would-be patients - after all, if a couple is determined enough, they can fool a GP as well.

"We try to do our best, but we should not have to turn practitioners into the border police for fertility treatments."

We want healthy children in happy, stable homes

Ruth Deech, chairman, HFEA

Increasingly, couples denied treatment in more restricted countries, such as the UK and France, are prepared to travel long distances to find doctors who are prepared to push the boundaries.

In France, it is illegal for any woman to have fertility treatment after the menopause.

Italy, Belgium and the US are the countries which have the most likely combination of skilled specialists and looser regulation.

One, Dr Severino Antinori, from Italy, has become notorious in the IVF community for his willingness to carry out procedures which the vast majority of his peers would never contemplate.

Ms Deech said that while international agreements to stamp out the worst ethical excesses would be desirable, implementing them would be "impossible", not least because different countries did have discernable differences in what is considered acceptable.

However, she added: "We're pretty sure it could not happen here."

Deciding who gets fertility treatment is likely to become yet more difficult in the coming years, as specialists find their model of a "happy, stable family" is increasingly challenged by gay couples, and single women.

Dr Fishel said: "It's a minefield - but then, reproduction and people's views about procreation are, and have always been, that way."