What do Adam, Eve and the Queen of Sheba have to do with libel reform? Ask David Balding and Mark Thomas, geneticists at University College London (UCL) who received legal threats after they criticized the claims of a firm that sells people details of their genetic ancestry. Or ask the student journalists who feared a libel lawsuit if they covered the row in their university newspaper. Or the senate committee of the same university that was forced to slap down its own rector for actions contrary to academic freedom.

It is a messy and perhaps uniquely British farce, and one that highlights the desperate need to change English libel laws. And it shows why long-promised reform, due to be discussed again in Parliament later this month, might not go far enough.

The story began last July, when Balding and Thomas heard Alistair Moffat, chief executive of genetic-analysis company BritainsDNA and rector of the University of St Andrews, tell BBC radio that his firm had discovered Eve’s grandson and nine Britons directly descended from the Queen of Sheba. He added that a volcanic eruption 70,000 years ago had wiped out all human lineages except those of Adam and Eve, that 97% of men with the last name of Cohen share a single genetic marker and that one-third of British men are descended from the country’s founding lineages. “The Bible, through BritainsDNA, is really starting to come alive,” announced Moffat, a historian.

Nonsense, Balding and Thomas said in a series of private letters and e-mails to Moffat and his company. Noting that scientists at Britains­DNA had trained at UCL, and concerned for the university’s reputation, Balding wrote: “Do you hope to maintain respectable scientific careers and also lend credibility to such nonsense?” Last September, he and Thomas received a letter from Moffat’s lawyers, demanding that they did “not report or state as a matter of undisputed fact that our client’s science is ‘wrong’ or untrue”.

As Nature knows to its cost, libel cases are expensive and time-consuming. But Balding and Thomas decided that they were on solid enough scientific ground to go public with their criticism of the science.

Under present laws, just the threat of a lawsuit is enough to silence reasonable criticism.

BritainsDNA looks at ‘uni-parental’ genetic markers on the maternally transmitted mitochondria and the paternally inherited Y chromosome. The Adam and Eve to whom Moffat referred are not those in the Bible, but individuals who lived in Africa 150,000–200,000 years ago and who had Y chromosomes and mitochondria that can be traced to humans alive today. These individuals are not special: their lineages are two among many that contributed DNA to modern humans.

Moffat’s claims about Adam and Eve, then, were meaningless, Balding and Thomas argued in several blog posts. Others, they considered, were flat wrong. Nobody knows which genetic markers the Queen of Sheba possessed, they said, and it is very unlikely that the eruption of Mount Toba in Indonesia 70,000 years ago wiped out all genetic lineages but those of ‘Adam’ and ‘Eve’.

Such overreach is a worldwide problem. The American Society of Human Genetics in Bethesda, Maryland, has twice issued policy papers that call on genetic-ancestry companies to state clearly the limitations and uncertainties in the information that they sell.

Balding and Thomas never heard back from Moffat or his solicitors. But a student journalist at the University of St Andrews, where Moffat’s position of rector is non-executive, received legal threats when he attempted to report the duo’s concerns. Jonathan Bucks, news editor for The Saint, says that Moffat repeatedly warned that if necessary, he would take legal action over anything the student newspaper published.

Senior members of the St Andrews academic senate launched an investigation into Moffat’s threats to Balding and Thomas, and concluded that they were “contrary to the principles of academic freedom and scientific debate in a matter of public interest”. The student newspaper ran its story, and did an excellent job.

Moffat may perhaps have been bluffing about his legal threats (he and his lawyers did not respond to queries from Nature) but under present laws, just the threat of a lawsuit is often enough to silence reasonable scientific criticism. It is right that reforms currently being considered by the nation’s Parliament would offer special protection to claims made in peer-reviewed articles. But only a clear public-interest defence for all scientific debate, at present not included in the reformed laws, will grant scientists the freedom that they need to speak out to safeguard public trust.