The statistics agree that women are disproportionately represented in science (see Nature 426, 8; 2003). But there is little agreement on how to redress the balance. Some plans call for legislation, others for quotas. Some advocates hope that female pioneers will lead the way, while others worry that high-profile successes will be accused of getting breaks because of their gender.

But the first step is to recognize a problem. The European Commission (EC) has taken that step and is trying to address it by asking grant applicants to provide gender-equality plans for their research teams in the current round of EC funding. Many scientists, however, are uncomfortable with the idea of legislating for gender equality (see page 210). Similarly, when European research centres have tried to target women for their ranks (see page 211), their projects attracted many qualified applicants — but also charges of reverse discrimination, inevitable in any quota system.

Even the pioneers disagree. Persis Drell became director of research at the Stanford Linear Accelerator Center in California last year, but says that she has reservations about being regarded as a role model for her gender. Biologist Shirley Tilghman, president of Princeton University, New Jersey, since 2001, takes the opposite approach, canvassing for more women in science.

As women scientists in Europe begin to rise to the top of their careers, they must grapple with similar issues. But at least that is starting to happen. Harriet Wallberg-Henriksson will become the first female president of Stockholm's Karolinska Institute next year.

Yet ultimately, it may be that market forces resolve the problem. If, as planned, Europe does increase its investment in research and development to 3% of gross domestic product by 2010, there won't be enough male scientists to do the work.