Genetic screening of human embryos may eventually eradicate inherited diseases ranging from breast cancer to cystic fibrosis.
Using a technique known as pre-implantation genetic diagnosis (PGD), specialists can select a couple's healthy embryo for implantation in the womb and discard ones that are damaged.
The technique is generally used for couples affected by a known inherited disease, most commonly severe conditions such as Huntington disease or cystic fibrosis.
Australian PGD pioneer Dr Leeanda Wilton - who has been working in the field for more than 20 years - said it had the potential to eradicate diseases that have haunted a family for generations.
''[The parents] … don't want to see future generations suffer as maybe their parents, or an aunt or uncle, have suffered,'' she said. ''If you have the choice to do that, why wouldn't you?''
But the idea does not sit easily with many medical ethicists.
When the first baby in Britain designed to be breast cancer-free was born this year it created an ethical storm, with anti-abortion campaigners saying it was morally wrong to deny life for imperfect babies.
Josephine Quintavalle, of the British-based Comment on Reproductive Ethics, said it was better to focus on finding a cure for inherited diseases than eliminating carriers.
Embryos rejected due to disease can be used for research into that condition, with the couple's permission.
Bernadette Tobin, an ethicist at Australian Catholic University and directs St Vincent's Hospital's Plunkett Centre for Ethics, said if ''you think that PGD is a morally acceptable means to avoid having a child with a serious genetic disorder depends primarily on the view you take of the moral status of the human embryo. Is it or is it not the kind of being which is worthy of our protection?
''If it is, then creating embryos with a view to selecting some and rejecting others is a morally unacceptable means to avoid having a child with a serious genetic disorder.''
To many couples affected by an inherited disease, PGD seems the best option available to them.
''Most people, once they are aware they have a problem, they can either choose not to get pregnant again or they can get pregnant and keep their fingers crossed, or they can test during pregnancy and possibly face the heartache of termination,'' Sydney IVF medical director Dr Mark Bowman said. ''PGD is a viable option. It has a very high success rate.''
Between 5 and 10 per cent of Sydney IVF's patients are there to undergo PGD and it is a figure that is growing as technology improves.
There are about 100 babies born in Australia each year using PGD, a small proportion of the 10,000 live births due to IVF.
IVF Australia medical director and president of the Fertility Society of Australia Professor Peter Illingworth believes this will increase as the public becomes more aware of the role genes play in their health. That will pose ethically difficult questions for the medical and broader community.
''The whole area of genetic testing is a complete minefield,'' he said. ''There is a concern that we could end up in a world where genetic testing is used for trivial reasons and embryos with minor imperfections are disposed of.
''It is possible that we could identify, say, the goal-kicking gene and that may be something that parents would want for their son. But the question is: is that something we should test for? This is never going to be easy technology.''
US IVF specialist Dr Jeff Steinberg caused a stir this year by offering couples the option of choosing their offspring's hair colour, eye colour and skin tone using PGD. Widespread condemnation saw the plan abandoned.
Dr Bowman said it's impossible to guarantee physical, athletic or intellectual traits using PGD - ''although American marketing would have you believe otherwise''.
''This is not a frivolous exercise,'' he said. ''We want to create healthy babies.
''We are testing for serious genetic diseases, we're not manipulating embryos or designing babies. I and most others in the profession have huge concerns about that.''
Human Genetics Advisory Committee chairman Professor Ron Trent also rejected the notion of the ''designer'' baby and the suggestion that gene technology would be used to create a master race.
''In the vast majority of cases, people ask for genetic testing for relevant medical reasons,'' he said. ''Potentially, there could be a test for athletic ability or intelligence in the future. And if people want to do that and they are willing to pay for it outside the public health system, why shouldn't they be able to?
''That said, the elite athlete is a complex person and while genetics plays a role in their ability, so do a lot of other exterior factors. I know some claims in the scientific community are somewhat exaggerated when it comes to what can be tested.
''Personally, I think people who want that sort of test are wasting their money and if they want to waste their money, it's their right to do that.''
Sex selection for non-medical reasons using PGD has been banned in Australia since 2004 but the National Health and Medical Research Council's Australian Health Ethics Committee is reviewing the decision.
Dr Bowman said he believed the ban, which forces couples wanting to choose their child's gender to travel overseas for treatment, should be overturned.
Of greater concern to many in the field is the expense of PGD, which can cost up to $13,000 and is not funded by Medicare.
Director of the Centre for Genetics Education Associate Professor Kris Barlow-Stewart said: ''It's only available in the private sector so there is an issue of equity there.. I would like to see it become a more available option in situations where it is appropriate and relevant.''
Dr Bowman is lobbying the Federal Government for funding to support PGD. ''The Government's position is a bit callous, to be frank, and it doesn't make any economic sense,'' he said.
''A baby with a major lifelong disability will cost the health system millions of dollars. And yet the Federal Government is quibbling over a few thousand dollars to give people a treatment to ensure a healthy baby. The Federal Government is always talking about preventative health.
''Well, PGD is the ultimate in preventative health.''
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