Harvard President Lawrence Summers stirred controversy earlier this year with his comments on the lack of women in the sciences. But if he had poked his head into a geology class at Yale, he might have noticed that women geology and geophysics majors at the University consistently outnumber men.

Martha Bell ’04, who double majored in archeology and geology and geophysics, said her major classes were dominated by women during her time at Yale. The discrepancy could just be a function of the Geology and Geophysics Department’s relatively small size, Bell said — for the Class of 2006, three of the department’s four majors are women — but statistics from the National Science Foundation suggest that Yale is not an anomaly.

The proportion of women receiving a bachelor’s degree in earth, atmospheric and ocean sciences has been rising for more than a decade. In 1990, 29 percent of people earning a bachelor’s degree in the geosciences were women, but by 2000, that number had increased to 40 percent. Still, the number of women remains low in geology Ph.D. programs, according to the data.

Possible reasons for the disparity are as numerous as layers of sedimentary rock.

“I don’t know why it happens,” geology professor Danny Rye said. “We actively recruit everyone, and that’s who we get.”

Students and faculty in the department said that the lower number of female graduate students and faculty could be the result of a lack of professors to serve as mentors to female students. In the department there are three female professors out of a total of about 35.

Yale is not the only university facing this imbalance. Kristine Pankow, professor of geology and geophysics at the University of Utah, said this ratio is typical of most institutions.

According to the NSF data, women will not be equally represented in academic geoscience positions for another 40 years.

Yale geology professor Ruth Blake said women can often feel isolated in a department made up entirely of male colleagues.

“Being successful relies on unwritten rules and relationships,” Blake said. “I think men and others might take it for granted being part of the boys’ club.”

Blake said unwritten skills required for success could be taught if new women professors had better mentoring from upper-level professors of either gender.

Izzy Sims ’05, who double majored in art history and geology and geophysics, said that while she understands her peers’ complaints about a lack of support from faculty, she felt encouraged in her studies by her professors and her advisers at Yale.

Sims, who now works in the private sector, said she decided not to go to graduate school immediately after college so that she could explore other career options.

“I wanted to support myself financially and see what it’s like to work in an office,” Sims said.

Personal fulfillment is a common consideration among undergraduate women deciding between graduate work and other career paths, Pankow said. She said it is difficult for women to take time off to have children because it often comes during crucial career-building years. In addition, getting tenure at a university requires publishing many papers and having a good teaching record, pursuits that she said are highly time consuming.

“Women are seen differently no matter how much a husband contributes,” Pankow said. “[Women] are the primary caregivers.”

Geology and geophysics major Catherine Izard ’06 said balancing work and family in the future is a common concern among undergraduate women.

“It’s hard to get a Ph.D. and get tenure before you want to have a family,” she said. “That’s something a lot of people think about.”

But Blake said there are several examples of high-achieving women in the field of geology who also have husbands and children.

The Association for Women Geoscientists reports studies showing that two-thirds of the women in the National Academy of Sciences have one to five children.

In the association’s outline for its initiative to appeal to more women, the first goal is recruiting more undergraduate women to the major. Bell said she thinks Yale’s recruitment efforts are already effective.

“I felt encouraged to stay because I made good friends and I enjoyed it,” Bell said. “It attracted more students because the other students were friendly.”

Since Bell left Yale, she has been pursuing graduate work in geography at the University of Wisconsin. Pankow said she thinks more women students will follow this path because, like the continuous shifting of the tectonic plates, the field is constantly changing.

“That’s one of the great things about geology,” she said. “More avenues open up and it becomes more approachable to women.”