A design for life

Babies used to be born, now increasingly they are "created" by science. Two cases concerning genetic screening of embryos have raised concerns about the advent of "designer babies".

Six-year-old Molly Nash has already attracted more media interest than most people could expect in a lifetime.

Stricken with a rare and deadly genetic disorder, Molly's parents, Lisa and Jack Nash, decided to create a living, breathing solution.

Through artificial insemination, they chose an embryo that would have the exact type of cells that would help save their ailing daughter.

A more common way of determing your baby's sex

In August, Lisa gave birth to a baby boy, Adam. Now, stem cells collected from his umbilical cord, have been donated to Molly which will help his older sister to replace her diseased bone marrow.

The donation means Molly's chance of recovering from Fanconi anaemia has gone from 30% to between 85-90%.

The Nashes say their decision was straightforward - they wanted another child and decided to help their sick daughter in the process.

But critics say the process represents an unwelcome step towards "designer babies".

Stricter than the US

Some of the harshest condemnation has come from Britain, where laws in this area are stricter than in the United States.

For the Human Fertilisation and Embryology Authority, which licences and monitors human embryology research on behalf of the government, it is uncharted territory.

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James Yeandel, spokesperson for the HFEA, says it has never received an application of this sort.

Dr Vivienne Nathanson, head of ethics and policy for the British Medical Association, has suggested the technique would not be allowed under British law because of the possibility the child was being seen simply as a "medical product".

The science alone is not illegal. The genetic screening process, which is known as preimplantation genetic diagnosis (PGD), has been used several times in the UK to ensure families have healthy babies.

Motivation is question

The central issue in the Nash case is the family's motivation for PGD - did they choose to have a healthy baby because they wanted another child, or because they wanted a source to help cure their daughter?

By coincidence another major test of genetic ethics, this time in the UK, has hit the headlines at the same time.

Molly Nash, with her life-saver brother Adam

Alan and Louise Masterton of Monifieth, near Dundee, want to use PGD to select the sex of their next baby. The couple, who have four young sons, lost their daughter, Nicole, in an accident more than a year ago.

Choosing the sex of a baby is specifically banned in the UK but they are planning to challenge that under the new Human Rights Act.

Commenting on the case, Dr Evan Harris, a Liberal Democrat MP member of the BMA ethics committee, warns of the danger of designer babies.

"It is important that designer babies are not allowed to be created for social reasons," he says.

Accentuate the negative

"The current law on selection allows only negative selection to avoid implanting embryos with serious medical conditions but doesn't allow positive selection through implantation."

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But that does not rule out designer babies for British women. The HFEA concedes there is nothing to stop British women travelling abroad for treatment.

Regulation is more relaxed in countries which do not have a national health service and a handful of clinics in the US allow couples to specify the sex of their baby using genetic screening of embryos.

The process is perhaps most open to abuse in places such as China and India, where boys are valued more than girls.

Both countries already have an imbalance, something which is put down to the fact girls are deprived of food and health services, and females are more likely to be aborted or even killed as babies.

Ladies second

In countries such as Britain and the US there is no marked bias towards male babies. But research in the US has found that Americans believe an ideal family has a boy as the oldest child.

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While screening embryos for sex selection was originally devised for medical reasons - some genetic disorders apply only to boys - it's commonly used in the US for "family balancing".

At the Genetics and IVF Institute, in Fairfax, Virginia, a patented technology called Microsort is used to sift through sperm, sorting out those most likely to carry X or Y chromosomes, which determine a baby's sex.

Critics of the process fear this is the tip of the iceberg. PGD techniques are advancing quickly and scientists are on the brink of being able to test for a host of conditions, simply by screening an early embryo.

That raises the prospect of parents being able to specify what colour hair their children will have, the colour of their eyes, their IQ and even their personality.