A couple of years ago, I came across an unusual use for the term ‘extinct volcanoes’ (see Naturejobs 3; 24 January 2002). In the academic world, it seems, the phrase refers to tenured professors who have ceased to be productive and who simply occupy space and eat up resources, even though their passion has long since cooled.

But, as with most issues, there is a flip side. Some countries, notably in Europe, inadvertently cap ‘active volcanoes’ — professors of a ‘certain age’ who are still actively conducting research and publishing. Mandatory retirement for top scientists can actually promote brain drain at a time when Europe is trying to prevent it.

For example, when Alex Matter, who helped to develop one of the most promising cancer drugs, Gleevec (see page 348), reached 65, Swiss law meant that he had to retire as head of the oncology therapeutic area at the Novartis research department in Basel, Switzerland. Fortunately, Novartis found him work in Singapore, where he now runs the company's Institute for Tropical Diseases (see Nature 426, 588; 2003).

Frank Gannon, executive director of the European Molecular Biology Organization, recently argued that age discrimination in science should not be practised in Europe (F. Gannon EMBO Rep. 5, 221; 2004). He believes that if 79-year-old conductor Neville Marriner can still lead the orchestra of the Academy of St Martin in the Fields, then top scientists can still lead in research after they turn 65.

Both Gannon and I sympathize with the young scientists waiting for academic slots to open up when senior scientists retire. But we also wonder about the sanity of a system that blithely quenches brightly burning intellectual fires.