The government will announce on Friday that insurers will be able to use those results to refuse cover or to push up premiums for those born with genes that could lead to fatal conditions.
The decision makes Britain the first country to approve the commercial use of gene technology in this way.
The Genetics and Insurance Committee, an advisory body reporting to the Department of Health, has decided that a test used to identify a hereditary risk of contracting the disease Huntington's chorea is technically reliable.
Tests covering several other conditions, including hereditary breast cancer and Alzheimer's disease, are also awaiting approval.
Two years ago another advisory body, the Human Genetics Advisory Commission, recommended a moratorium on the use of information from such tests.
However, that advice was rejected by the government, which decided insurers should be able to use such information, subject to the Genetics and Insurance Committee agreeing a test's technical reliability.
The announcement is likely to fuel the ethical debate over the use of genetic information.
Critics fear that vulnerable groups could find it difficult to get a mortgage or life insurance, or face higher premiums.
But the insurance industry dismissed that suggestion.
No compulsion
Professor John Durant, chairman of the Genetics and Insurance Committee, told the BBC that nobody would be asked to take a genetic test by an insurance company.
Rather they would be expected to disclose the results of any genetic test for Huntington's disease they had taken in the past.
Professor Durant said this would not be a legal obligation, but insurance companies would have the right to refuse to offer insurance if a customer refused to reveal details.
He said: "It is not a punitive step. This will actually benefit very many people seeking insurance.
"The only people who are likely to have taken a test for Huntington's disease are people with a family history of this disease.
"Many of those people will actually have had results which show that they are fortunate enough not to have inherited the gene, so those people will be able to get insurance, at the moment they may well find it difficult."
Mary Francis, the Director-General of the Association of British Insurers, said that companies already asked potential customers about family history of disease.
She said: "This is really an extension of what already does happen."
Sue Watkin, chair of the Huntington's Disease Association, also said insurance companies were already using genetic test results to calculate or refuse premiums.
She said: "Our main concern is that people at risk of late onset genetic disorders should be able to get insurance of some kind up to a certain level.
"At present, many people are made offers they just cannot afford."
Ms Watkin said that a person at 50% risk of developing Huntington's often found their insurance premium loaded by as much as 300%.
She called on the government to establish a fund to be used to provide insurance for people at risk.
The National Consumers' Council is concerned people will be put off having tests because they feared that the results might count against them - with a possible knock-on effect on their health.
A spokeswoman said: "A person might think if I take a test I will know information that I don't know now, and maybe ignorance is bliss.
"If you don't know the information you can't put it on the form."
The Human Genetics Commission, another government advisory body overseeing developments in the use of genetic technology, said that it would launch shortly a major public consultation exercise about the use and protection of genetic information, which would include insurance issues.
The exercise would eventually result in the Commission making recommendations to ministers.