Insurers are at loggerheads with an influential committee of MPs over their enthusiasm for genetic testing. Companies now face a ban on the use of information from genetic tests because of fears they may create a genetic underclass.

The Commons Science and Technology Select Committee has recommended a two-year moratorium on the use of all positive genetic tests. If insurers refuse to stop using test results voluntarily, the Government should introduce legislation to force a moratorium.

The committee has also recommended that the Government insurance industry collaborate to provide an alternative form of insurance for those who would otherwise be denied cover because of their genetic make-up.

In a report published last week, the committee said a decision by the Association of British Insurers that several of the tests it recommended four years ago are no longer valid 'casts the gravest possible doubts' on those still used by the firms.

In a scathing attack on the industry, the committee said: 'Insurers appear to have been far more interested in establishing their future right to use genetic test results in assessing premiums than in whether or not they are reliable or relevant.' The ABI's code of practice bars companies from telling applicants to undergo genetic testing, but permits them to ask for the results of any tests they have already taken.

Insurers claim that if they ignore the results of genetic tests, customers who know they risk developing a hereditary disease will be able to buy large amounts of insurance at the normal price. However, three insurers - Virgin Direct, Standard Life and the Cooperative Insurance Society - do not require applicants to reveal the results of genetic tests, arguing that the numbers involved are so small that their effect is negligible.

In 1998 the ABI named 10 tests for seven conditions for which it believed there were reliable genetic tests, but reduced this to five tests for three conditions last year. Those left are for breast and ovarian cancer, Huntington's and early-onset Alzheimer's.

Only one, for Huntington's disease, has received approval from the parliamentary Genetics and Insurance Committee so far, but most insurers are using the results of all five tests when assessing risk. The Science and Technology Select Committee says this should stop immediately.