Women in pursuit of science careers are still fighting the same invisible barriers their counterparts fought in the 17th and 18th centuries, said a history professor who recently published a book on the subject.

In the work, "The Mind Has No Sex? Women in the Origins of Modern Science," Londa L. Schiebinger, assistant professor of history, focuses on how women in the 17th and 18th centuries were denied entry into science-related fields.

"Science is now one of the last strongholds where women haven't done very well and so I thought that was a very important field to tackle and look at the ways that women have been excluded from science," she said.

The book details important women, such as Marie Curie, and how they dealt with the prejudices in the scientific community. Curie was the first person ever to win two Nobel prizes, but for all of her success she was still denied access to the Parisian Academie des Sciences in 1911.

"I chose a historical topic, because it's easier to see how it works in the past," she said. "I think that same system is working today."

Invisible barriers affect women at every turn as they advance in science careers, Schiebinger said. These include lack of role models, lack of mentors, and the absence of women at the top of the career ladder.

"I think that if people are aware of the barriers, they can be overcome," she said. "Women have to become aware of them."

Sharon Jadrnak, director of the University's Women in Engineering Program, cited some of the subtle discriminations that take place in the classroom.

Men may be called on more often to answer questions than women, she said, and women's answers may be entirely ignored.

Also, during group projects, women rarely will be asked to lead or run the experiment, she said. In many of these cases the woman is reduced to a secretary, writing up the lab report.

At the University's College of Science, women make up 40 percent of enrollment in science majors, not including engineering, said Norman Freed, associate dean of the College of Science.

Women's enrollment dwindles in the area of graduate studies, he said. Only 30 percent of women with scientific degrees pursue post-college education, he said.

Although Schiebinger notes that subtle stereotypes continue to exist for women in science, she maintains a positive attitude.

"I'm optimistic, I think it's a good time to be a woman," she said. "We have lots of things going for us."