Dr Gillian Mitchell, head of the Familial Cancer Centre at Peter MacCallum Cancer Centre, said one risk of recreational genetics was offering up the ''mine of information'' contained in our DNA to companies identified only online.

Fairfax Media reported on Monday that 180,000 people had sent their blood or saliva to be analysed by 23andMe, a company that assesses health risks and genealogy. The service now costs $99, and similar kits from other companies are offered online in Australia from $300.

Dr Mitchell contrasted this service with more definitive tests available for breast cancer, for instance, where ''you take the DNA and look at every single bit of that gene to see whether it is normal or abnormal''.

In the tests offered online she said ''you are looking broadly across the genetic make-up trying to see subtle areas of difference and then making some predictions based on those''.

''Some of these companies can give different answers,'' Dr Mitchell said. ''It is not to say one is definitely right and one is definitely wrong; it is just the limits of our understanding.''

The genetic test results are also of interest to life insurers setting premiums, and must be disclosed as part of customer's reporting obligations under Australian law. Health insurance is not affected as companies cannot discriminate based on an individual's risk factors.

The Financial Services Council - whose 24 members account for more than 99 per cent of life insurance premiums - has issued binding guidelines on genetic testing.

Members ''will not require applicants to undergo a genetic test when they apply for insurance'', but ''will require applicants to make available the results of any previously undertaken genetics tests on request''.

Mark Fitzgibbon, managing director of NIB - a health fund with more than 880,000 customers - disagreed with those who worried about insurers misusing genetic information. ''If you take that argument to its logical extension we should never have any blood tests,'' he said.

''If the future means that genetic testing does raise the bar so to speak in terms of life insurance … that is an issue we have to deal with as a society and manage. But it can't be a reason not to garner better information about our genomes and therefore interventions which may improve our lives.''

Professor Graeme Suthers, a genetic pathologist and spokesman for the Royal College of Pathologists of Australasia, said people should be active in their own treatment, but that online genetic testing lacked the ''chain of accountability'' of conventional pathology. '' He said he wouldn't trust online test results.