The new field of bio-history needs a code of ethics, says a Chicago group of scientists, historians and lawyers in the journal Science. Biohistory involves the use of genetic tests of historical figures. Researchers have tested strands of Beethoven’s hair, for instance, and studied the remains of African slaves in a New York City graveyard. Many museums are now mulling over how to deal with bones or clothing of famous people. “The potential is enormous for answering historical questions through testing of these artefacts,” says Lori Andrews of the Illinois Institute of Technology.

However, unrestricted use could involve ethical problems. Some argue that descendants should be consulted because the information might affect them. Sometimes it could trivialise an historical figure. The Chicago group, for instance, wants guidelines on what can be done with blood-stained artefacts related to the assassination of US President Abraham Lincoln. Some investigators want to see if he had a genetic condition known as Marfan syndrome. Others wonder if they might be related to him. Others see a commercial value in them, such as the company that wants to incorporate Lincoln’s DNA into a line of up-market jewellery.