The under-representation of women in science careers in the United States has been reported before, but a new Cornell University report provides more – but not necessarily startling – details about why this under representation occurs. The Cornell researchers’ conclusion explains the situation along fairly commonsensical lines: The choice to have and raise children unfortunately coincides with difficult career periods.

A good starting point on this issue is a study published last July by the Center for Work-Life Policy. It reported that 52 percent of women in private-sector science and technology jobs drop out without returning. The study also revealed that there was a specific age range, 35-44, where the attrition peaked. This is dropout pattern exists despite evidence that gender differences in science study are starting to level out. According to the National Science Foundation, nearly half of the students pursuing graduate degrees in science, technology, engineering and math are female. In the biological sciences, women dominate at the graduate level, making up 56 percent of the student population.

The Cornell study was actually framed to answer the question of why women tend to choose non-math-intensive fields for their careers. The answer they found indicated that it that the choice had little to do with mathematical ability and a lot to do with wanting the flexibility to engage in parenting and caregiving. “A major reason explaining why women are underrepresented not only in math-intensive fields but also in senior leadership positions in most fields is that many women choose to have children, and the timing of child rearing coincides with the most demanding periods of their career, such as trying to get tenure or working exorbitant hours to get promoted,” said lead author Stephen J. Ceci, professor of human development at Cornell. “These are choices that all women, but almost no men, are forced to make,” said co-author Wendy M. Williams, Cornell professor of human development.

The Cornell study is published in the March issue of the American Psychological Association’s Psychological Bulletin (135:2). It integrated 35 years of research on sex differences in math. The researchers acknowledge that sexism may still be a factor, but as only one of several. “Institutional barriers and discrimination exist, these influences still cannot explain why women are not entering or staying in STEM careers,” said Ceci. “The evidence did not show that removal of these barriers would equalize the sexes in these fields, especially given that women’s career preferences and lifestyle choices tilt them toward other careers such as medicine and biology over mathematics, computer science, physics and engineering.” “Women would comprise 33 percent of the professorships in math-intensive fields if it was based solely on being in the top 1 percent of math ability, but they currently comprise less than 10 percent,” Ceci said.

Policy decisions can lessen the consequences of women who face difficult career-family choices. The authors have drafted several recommendations for new options for women. Their suggestions include delayed or deferred entry to tenure-track positions, part-time-to-full-time transitions in tenure-track work and more frequent use of “courtesy” appointments that would provide enough financial and technical support for women to continue their research from home. P.S. There are many resources about and for women in science. One of the newer ones is “Under the Microscope,” a website developed in 2008 by the Feminist Press and IBM with funding from the National Science Foundation. Besides insightful blog posts, you find links to books such as Base Ten (“I’d recommend this book to anyone, male or female, working in a scientific field and attempting to organize a healthy family life.”) and the Smithsonian’s flickr page of historical photos of women in the sciences.