Kay Davies, the leading geneticist, yesterday called for a national debate on the implications of genetic testing for the individual and society.

Launching a Ciba Foundation discussion on the issue at the British Association science festival, Professor Davies said that while genetics offers enormous benefits, the implications of this knowledge and the prevention of its abuse need to be debated openly.

Professor Davies, head of the molecular genetics group at the Oxford-based Institute of Molecular Medicine, said that it was particularly important to set up a framework to ensure the protection of "a patient's fundamental right to informed consent, autonomy and confidentiality." The computerisation of medical records and the move towards widespread screening makes this particularly challenging, she said.

In highlighting some of the medical advances that have been made thanks to molecular genetics, Professor Davies said that it is now possible to diagnose most common single gene defects such as muscular dystrophy and cystic fibrosis.

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Screening for susceptibility to certain cancers such as colon cancer and a small proportion of breast cancer is also possible. In the near future, it will be possible to predict an individual's risk of having a predisposition to more common disorders resulting from genetic/environmental interactions such as diabetes, heart disease, mellitus, asthma and rheumatoid arthritis.

Tests are now easier and much quicker to do, opening up the prospect of the genetic screening of populations. Professor Davies said that population screening, prenatal diagnosis and pregnancy terminations have already had a major impact on the incidence of single gene defects in certain populations. Screening for the neurological disease Tay Sachs among Ashkenazy Jews has resulted in its virtual eradication in this population.

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Many ethical challenges, however, are presented by these advances. The use that is made of the detection of disease genes, the implications of this information for an individual, the family and the population as a whole, all need to be discussed.

Professor Davies was also concerned at the prospect of employers and insurance firms tapping into genetic information: "Will people be compelled to have certain genetic tests in order to obtain insurance? In countries with limited public health care services, this is a major issue for private health insurance. Also, where health and life insurance are provided by an employer, these genetic tests have implications for career development."