Sir

It has been a few decades since families started raising their daughters to have high personal and professional ambitions. But still only a small minority of women remain in science after their postdoctoral phase — mainly those who have postponed or forgone motherhood, or are among the lucky few with access to high-quality affordable child care.

The fact that the issue of childcare availability is discussed in relation to women's careers (Nature 296, 446–447; 2005), instead of young scientists' careers in general, speaks for itself of the bias regarding the role of women in the family and in the workplace.

If women are to share positions that were traditionally occupied almost exclusively by men, what we need is not just affordable child care but a new social ‘family contract’, coherent with expectations about women's self-fulfilment and the maintenance of the family as an important institution.