For the price of a night out, individuals can learn key elements of their genetic composition from new DNA testing kit for booming private genetic testing market.
For Carole Kushnir, a test that she took out of simple curiosity about her genetic make-up revealed a double risk of cancer. And for Karen Durrett, it led her after half a century to a father she had never known - and also brought to light a potentially fatal condition.
The two women are among 180,000 people who have paid to have key components of their DNA analysed by 23andMe, the world's biggest private genomics company, to assess more than 200 genetic traits and health risks.
That number is expected to soar this year after the California-based company -- which takes its name from the 23 pairs of chromosomes in a normal human cell - dramatically reduced the cost of a testing kit to $99 last month, after an infusion of new joint venture capital.
Sales of the kits were a Christmas hit and the company, which was co-founded by Anne Wojcicki, the wife of Google entrepreneur Sergey Brin, is aiming to reach a million clients by the end of this year - some abroad, including in Britain. It is sold by mail order in Britain, though it does not record country-by-country sales figures.
But on the frontline of the new world of genomes and genetics, the boom in business and interest is unleashing a wave of controversy about the commercial use of one the most crucial medical breakthroughs of recent years.
For proponents such as Miss Wojcicki, whose husband has a genetic mutation that significantly increases the risk of Parkinson's disease, this is the dawn of an exciting new era.
For the price of a night out, individuals can learn key elements of their genetic composition, hence take life-saving treatment, or protect their children from health risks than run in their family.
But critics -- and that includes many doctors, bio-ethicists and geneticists - are just as alarmed that people will be overloaded with information that is difficult for them to interpret, raise unnecessary health fears or false reassurances, lead to unneeded procedures for diseases that might never develop or impose the stress of fears over conditions that cannot, for now at least, be cured.
"There are major concerns about the private genetic testing market," said Helen Wallace, director of GeneWatch UK, a genetic watchdog group.
"It is unregulated, much of the information people get is misleading or unreliable and genetic tests are a poor predictor of the big killer diseases. And there is also the danger of people receiving scary surprises without the presence of a doctor for which they are not prepared."
Mrs Kushnir, 69, who owns a chain of hair salons with her husband in California's hi-tech heartland of Silicon Valley, is scornful of such concerns.
"It's patronising in the extreme, particularly in the era of the internet when people go to their computer to check the symptoms if they just get a sore throat, to argue that only experts can handle this sort of information," she told The Sunday Telegraph. "That assumes a dumb consumer."
She took the test last year out of curiosity. "Here I was in Silicon Valley, surrounded by all these technology start-ups, so I thought that I would give it a go," she said.
To take a test, a client spits into a test tube or swabs the inside of the check, then sends the sample for analysis to companies such as 23andMe. Laboratories look for common genetic variants that can indicate a risk of diseases that include Alzheimer's, diabetes, several cancers, Parkinson's and obesity.
There was no family medical history to alarm Mrs Kushnir. But to her surprise, the test revealed that she had a mutation in the BRCA2 gene that put her at risk of breast and ovarian cancer.
"I had very mixed emotions," she recalled. "I was obviously not happy to discover that I had the mutation, but relieved to have the information so that I could do something about it. This would not have come up in a routine medical visit."
After follow-up tests, a cancer specialist advised her that the threat of breast cancer could be monitored by regular examinations. But as ovarian cancer is more difficult to detect early, he recommended that she have her ovaries removed -- the option she took.
She encouraged other family members to take tests too. Several, including one of her sons, discovered that they also had a similar genetic mutation that heightened their cancer risks and are now receiving medical treatment.
But recent focus group findings and professional surveys illustrate the deeply-held and diverging opinions over the how to use these potent new weapons against disease.
Almost all parents have said that they want to be informed of every risk of disease for their children, however remote and even if currently untreatable. But most doctors, geneticists and bioethicists believe that only information that could lead to action should be shared.
The American Academy of Paediatrics recently expressed strong reservations about such testing for children except in limited circumstances.
The American College of Obsetricians and Gynaecologists has concluded that personalised genetic profiling is at this stage "not ready for prime time".
And in an effort to provide guidelines for what is still a fledgling field, the American College of Medical Genetics and Genomics is drawing up a list of "a few dozen" major conditions for which to search during testing for the most common mutations.
Even as the professional medical community tries to apply some rules, however, others are forging ahead.
Mrs Durrett, 53, from Roswell, Georgia, decided to take the DNA test to try to determine the cause of some minor health problems after watching a television programme about the new technology.
But her experience illustrates another side-effect of such genetic soul-bearing -- the exposure of the long-held secrets that can tear apart families.
For she not only ended up discovering that she had breast cancer; she also learned that the man whom she had called "Dad" for 50 years was not in fact her father.
Mrs Durrett's suspicions were initially aroused when unexplained relatives seem to be coming up as matches in the 23andMe database. She approached her mother, who revealed to her that she was the product of a brief teenage relationship, not the daughter of the man who raised her.
Mrs Durrett subsequently tracked down her birth father and bonded with a half-sister she never knew she had. That half-sister was battling breast cancer, she learned, so when an update from 23andMe revealed that she also had an elevated risk of the same disease, Mrs Durrett went to see her doctor.
A subsequent biopsy found that she had cancer in the milk ducts of her breasts. She underwent two lumpectomies and 33 rounds of radiation to treat the condition.
"If I'd waited, it would have gone into the tissue," she said. "That's my reality. There are lot of people who have fascinating DNA stories and they just don't know it yet."
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