research director Nobels in science.

Daniel Louvard does not believe in affirmative action. Time and again, the scientists in his Left Bank cancer laboratory have urged him to recruit with gender diversity in mind. But Louvard, research director at the Institut Curie and one of France's top biochemists, just keeps hiring more women. "I take the best candidates, period," Louvard said. There are 21 women and 4 men on his team.

The quiet revolution that has seen women across the developed world catch up with men in the work force and in education has also touched science, that most stubbornly male bastion.

Last year, three women received the prestigious Nobel prizes in the sciences, a record for any year. Women now earn 42% of the science degrees in the 30 countries of the Organization for Economic Cooperation and Development; in the life sciences, such as biology and medicine, more than 6 out of 10 graduates are women.

Younger women, too, are sticking more with science after graduating: In the European Union, the number of women researchers is growing at a rate nearly twice that of their male counterparts, giving rise to what some have dubbed a fledgling "old girls network."

Even Barbie, the iconic doll who in 1992 was infamously made to say, "Math class is tough," has had a makeover as a computer engineer for her 2010 edition, complete with pink glasses and pink laptop.
But if the progress has been dramatic since the physicist

Marie Curie, who won the Nobel prize twice, was barred from France's science academy a century ago, it has been slower than in other parts of society — and much less uniform.

In computer science, for example, the percentage of female graduates from American universities peaked in the mid-1980s at more than 40% and has since dropped to half that, said Sue Rosser, a scholar who has written extensively on women in science.

In electrical and mechanical engineering, enrollment percentages remain in the single digits. The number of women who are full science professors at elite universities in the US has been stuck at 10% for the past half century. Throughout the world, only a handful of women preside over a national science academy. Women have been awarded only 16 of the 540 Nobels in science.

The tug-of-war between encouraging numbers and depressing details is in many ways the story of the advancement of women overall. Women get more degrees and score higher grades than men in industrialized countries. But they are still paid less and are more likely to work part time. Only 18% of tenured professors in the 27 countries of the European Union are women. And the big money in science these days is in computers and engineering — the two fields with the fewest women.

In the 21st century, perhaps more than ever before, there will be a premium on scientific and technological knowledge. Science, in effect, will be the last frontier for the women's movement. With humanity poised to tackle pressing challenges — from climate change to complex illness to the fallout from the digital revolution — shortages of people with the right skill sets loom in many countries. Therein lie both opportunity and risk for women: In the years to come, the people who master the sciences will change the world — and most likely command the big paychecks.