There is a common misperception that genius and exceptional scientific achievement are the preserve of the young. A News Feature on Science after retirement age: Breaking the age barrier of this issue shows the limitations of this view: some scientists are performing creative and groundbreaking work into their 70s and beyond. Yet many of them feel frustrated at what they see as unjustified obstacles in their path — including, in some countries, mandatory retirement for university professors.

Mandatory retirement policies were generally introduced, along with decent pension provisions, to ensure dignity and leisure for the old, while opening up job opportunities for the young. But there is a big difference between being forced to work to avoid penury and doing so because you love what you do. Most scientists' work is far more than just a job — it is a vocation, pursued with a passion that cannot be switched off overnight.

And nor should it be. Carl Friedrich Gauss may have surprised his school-teacher at the age of seven when he worked out the factorial of 100 in his head. But although the German mathematician made many of his important discoveries before he was 20, he continued to make progress in a wide variety of fields into his seventies. Charles Darwin wrote two of his best books, The Descent of Man and The Expression of the Emotions in Man and Animals, in his sixties.

Science needs the energy and freshness of vision that youth can bring, but it can also benefit from the perspective and experience of age. The qualitative research that has been done on the matter reinforces the common-sense view that groups of people from a wide range of backgrounds are better at problem solving than are homogeneous ones. Science needs to take steps to keep the door open to exceptional older minds.

This must not, however, mean closing the door on younger researchers. In some countries — Germany and Japan spring to mind — the security and immovability of a ruling caste of established senior professors sometimes does just that. Even in countries with more flexible university systems, such as the United States, it has never been tougher for young scientists to win faculty positions (see Nature 422, 354–355; 2003).

At the same time, most countries face demographic and financial pressures that are forcing them to reconsider their general approach to mandatory retirement. Falling birth rates and higher life expectancy mean that there will soon be far fewer working people to support pensioners' income, from public or private sources. Poor stockmarket performance and inadequate provision for state pensions compound the problem. The subsequent discussion of higher retirement ages doesn't thrill the public. But in science, it should allow for a fuller consideration of measures that will tap the energy of older researchers who want to keep working.

It is time for policy-makers and university administrators to look more imaginatively at ways of structuring academic careers to introduce greater flexibility and alternative options. Just as science stands to benefit from arrangements that will better accommodate women with children, or attract more interest from ethnic minorities, it can benefit from active measures to help older researchers who still have what it takes.

Greater use of the ‘emeritus professor’ system, where researchers keep an association with an institution while drawing their salary from their pension, can tap the brains of older specialists who are no longer active in research. Research institutions and governments should also be searching for ways to accommodate those who want to remain active in research and have a contribution to make.