Should we all have our genomes sequenced? Two experts debate the issue on bmj.com today.

Professor John Burn from the Institute of Genetic Medicine at Newcastle University says sequencing everyone's genome would give us unparalleled knowledge to prevent, diagnose, and treat disease.

"Genetic predisposition plays a central role in most common diseases," he writes. "Clinically relevant discoveries are entering practice at a rate of more than 30 a month."

He acknowledges that "our capacity for interpretation is still rudimentary so we must ensure we have explicit consent to retain sequence data linked to patients' records." But adds that "only by analysing sequence data and phenotypes across large patient populations will we understand which bits of genetic information are clinically relevant."

"We must understand our limitations," he says. But he argues that linking whole genome sequencing to clinical outcomes "will have profound influence on drug discovery and development." High speed sequencing of pathogens will also revolutionise response to epidemics worldwide, he adds.

But Professor Frances Flinter from Guy's & St Thomas' NHS Foundation Trust in London, argues that possessing the technical ability to do something new is not an immediate justification for going ahead with it, especially in such an ethically complex area.

She says government plans to sequence the genomes of 100,000 NHS patients with cancer and rare diseases in the next 3-5 years "are sensible, as detailed knowledge of individual phenotypes will support data interpretation, increasing the library of reference information available."

However, she warns that sequencing the genome of every individual is a very different proposition, saying "Our current, extremely limited, knowledge of most of the information that would be generated means that providing a meaningful interpretation is impossible."

She believes that, "if we sequence individuals' DNA and tell them that they are genetically predisposed to be slightly more at risk of common diseases, we may be doing them a great disservice, de-motivating them from behaving sensibly; while the private sector will see a marketing opportunity for all sorts of clinically unnecessary and potentially damaging screening, with further negative and unintended consequences."

"Currently whole genome sequencing in healthy individuals has nothing to offer clinically, as most of the data generated are meaningless; the maxim first do no harm still holds," she concludes.