Clinical geneticists and medical ethicists have welcomed guidance from the General Medical Council that says that doctors may share confidential genetic information to protect a patient’s relatives, even if the patient objects.

The guidance focuses explicitly for the first time on genetic information that could benefit a family member as a possible exception to the rule that patients’ data must be kept confidential.

Previous advice in 2004 stated only the broad rule that doctors could disclose patients’ data if the benefits to an individual or society outweighed the public’s and the patient’s interest in keeping the information confidential.

The new advice follows advances in medical science and a recommendation by the …