A range of United Nations agencies are calling for the practice of female genital mutilation to be ended within the space of a generation.
An estimated three million girls a year are thought to be at risk from this practice, many of them in Africa.
The practice of cutting off the clitoris of a young girl - and often more - is deeply rooted in some cultures.
Ten UN agencies want a major reduction in the tradition by 2015.
The practice is seen in some countries as a way to ensure virginity and to make a woman marriageable.
Yet it also leads to bleeding, shock, infections and a higher rate of death for the women's new-born babies, say the UN groups.
Up to 140 million women are thought to have undergone this procedure in 28 countries in Africa, and a few in Asia and the Middle East.
It is also happening to girls and women who have left their original countries and settled in the West.
The UN agencies say traditions are often stronger than law and legal action by itself is not enough to tackle this.
Change must come from within communities, they say, citing the example of West Africa, where villages have joined together to make pledges to abandon this practice.