Over-the-counter DNA tests could lead to people making poor or wrong assumptions about their future health, according to a new report.

The genetic testing kits, available in shops or online, suggest insights into ancestry, disease risks and information on personality, athletic ability, and child talent.

However Anneke Lucassen, professor of clinical genetics at the University of Southampton, said the results can "easily be misinterpreted".

She said people can expect these tests to provide clear-cut answers about their future health, and can be highly predictive and informative, whereas in fact interpretation of the data is both "complex and context-dependent".

Writing in the British Medical Journal, Professor Lucassen said that false positives - where results indicate a person has a high genetic risk of a disease or condition when they do not - are common, while false negatives may "reassure" at-risk people that they have little to worry about.


She added that most people with apparent "positive" results will not go on to develop the related condition.

The report said: "Genetic data is complicated, and can easily be misinterpreted.

"Direct to consumer (DTC) genetic tests are sold as providing answers, and patients may understandably expect that their results will be clearly predictive of future health.

"These expectations, driven by marketing and media coverage, leave people at risk of over-interpreting results from DTC genetic testing."

The article also lays out advice for GPs confronted by worried patients. It said they should put the results in context for their patients, discuss possible sources of error and, if appropriate, shift the conversation from genetic risk to lifestyle changes that could help to reduce the likelihood of future disease.

If a patient is concerned about a "bad news" test result, they should be offered a genetics appointment if they also display symptoms that may indicate the person has the condition in question.

Regardless of any "reassuring" results, GPs are urged to refer anyone with a medical or family history who they would otherwise offer a genetics referral.

The report adds: "The assumption that DTC genetic testing empowers people to reduce their future disease risk is undermined by evidence that suggests that learning about genetic predisposition to particular diseases rarely leads to sustained lifestyle change."