Government advisors have called for tighter controls on genetic tests sold directly to the public.
Several tests for genetic risk of disease are on the market
The Human Genetics Commission said all of them should be independently reviewed before reaching market.
Tests with major health implications should not be advertised directly to the public, and should only be administered by a health professional.
Experts said the science was not yet good enough to support the predictive value of many tests.
Review the European Directive which deals with genetic tests to scrap loopholes exempting them from thorough pre-market evaluation
End advertising directly to the public for tests with significant health implications
New system of regulation for non-medical "lifestyle" tests which fall outside the European Directive
Since 2003, there has been a marked increase in the number of companies providing genetic tests.
Examples include tests for certain types of cancer, such as prostate cancer, and tests for conditions such as osteoporosis and heart disease risk factors.
The HGC said there was also a "burgeoning cottage industry" in lifestyle tests, offered in conjunction with dietary supplements and medications.
Under European rules, these tests are currently classed as low risk, meaning they do not have to be independently reviewed by experts before they are launched.
The HGC said stricter controls should be in place and the Medicines and Healthcare products Regulatory Agency should be responsible for overseeing that standards are met.
The HGC said they did not want to ban any tests.
But a company should have to convince the regulator that the test is suitable and anyone involved in providing it has the right training and expertise to give good advice.
The Office of Fair Trading and Advertising Standards Authority also need to be involved in whether claims made by tests can be substantiated, the HGC added.
Sir John Sulston, HGC chair, said: "There is no doubt that many tests provided without the involvement of a doctor or a health professional could cause people totally unnecessary alarm or give them false reassurance.
"We have a burgeoning industry here and we urgently need regulation to match."
Christine Patch, member of the HGC and consultant genetics counsellor at Guys Hospital in London, said they had first looked at the issue in 2003 when there were not many companies in the marketplace.
"I see families who are at a high risk of a genetic condition. If you are offering a service for people who want to know about their risk then there are standards you should meet," she said.
"You need to offer full information on what it might mean and what you can do with the results. "You need pre- and post-test counselling."
She added that for tests which determine risk of a condition, such as heart disease or diabetes on the basis of several genes, the science was not yet strong enough.
There are three companies offering genetic testing services in the UK.
The US has the highest proportion of companies, many of which can be accessed by overseas clients through the internet.
Stuart Hogarth, an expert on regulation of genetic tests from the University of Nottingham, said the US, Canada and Australia all had tougher regulation for genetic tests than Europe.
"We haven't developed any standards," he said.
"It needs to be decided at the European level and the current consensus is it's not fit for purpose."
A Department of Health spokesperson welcomed the report, and would consider its recommendations.