Of the 600-odd Yale College women who will receive their diplomas at Commencement, few will leave New Haven this spring with degrees in the sciences.

Women make up fully half of Yale’s undergraduate enrollment, yet a disproportionate few choose majors in the fourth distributional group.

This discrepancy within Yale’s student body belies a similar trend among professors: if Yale attracts few female science students, it employs even fewer female science faculty.

Although this gender gap exists at most other top universities — and to an even greater extent in the corporate world — Yale recently approved several changes to its human resources policy that will allow female faculty members to better balance childbirth with career.

In 2000, women accounted for only 15.8 percent of Yale’s tenured faculty members, according to data from the University’s Office of Institutional Research. Women accounted for 33.7 percent of Yale’s non-tenured faculty.

Several women who are graduating this spring with degrees in the sciences said the presence of female faculty in the fields would attract more female students.

The new changes, recommended by the Committee on the Economic Status of the Faculty, would allow female junior professors to take longer leaves of absence after childbirth without cutting short their terms of appointment.

The arrival last July of Yale’s first tenured female physics professor, Meg Urry, was a first step at increasing the presence of women in the physics department, where none of the three physics majors graduating this year are female.

Olivia Billett ’02, an astronomy and physics major, said Urry’s presence at Yale was encouraging to women majoring in physics.

“It is really nice to have a role model. It’s a subconscious thing that you don’t even notice,” Billett said. “When [Urry] was on the list of possible advisors for senior projects, I was surprised at how happy I was to see a woman there.”

The lack of female role models, along with the sheer difficulty of the material, can very often discourage entrance into the field.

“Perhaps a lack of role models makes it difficult for some women to enter physics. Astronomy and physics can be very difficult — It helps to have a friend or two, or a parent or professor, who believes that you can do it even when you don’t believe you’ll ever understand any of it,” said astronomy and physics major Beth Yale ’02.

Chemistry professor John Faller suggested that there are so few women in his field because the amount of time involved in chemistry is not commensurate with raising a family.

“Many more [women] go into biological science than physical science,” he said.

Despite the various departments’ efforts to find female candidates, the biggest obstacle seems to be the small pool of female math and science professors nationwide. Even when there are female professors in fields where Yale is hiring, their credentials often do not meet the University’s standards.

“If we have two equal candidates, the female would get it — but oftentimes they can’t compete with the men. It’s quality first,” said physics professor Michael Zeller.

Sometimes obstacles for females in a male-dominated field may not be immediately apparent. Urry said she has been excluded from conversations about promotion opportunities and has been denied the same challenges and responsibilities as her male colleagues.

For some students, many of the difficulties are subconscious.

“After four years of physics classes taught by men, full of men, about men’s discoveries, and TAed by men, you begin to think that men are supposed to do this. They are also a lot more confident on average, so you believe that they are smarter,” Billett said.

Several students and professors also attribute the lack of women in mathematics and science to deeply-rooted gender biases and stereotypes in society.

“Girls need to be exposed to successful female scientists at an early age before they automatically associate the field with men. That way, they won’t let external pressures diminish their interests in the sciences,” said physics major Michael Soskis ’02.