TOKYO — When she meets people off campus, Junko Tsuchiyagaito, 23, does not usually let on that she studies chemistry at the graduate level. She does not deliberately withhold the information, but she does not volunteer it, either.

She said that Japanese women who studied the humanities were seen as being more polished and attractive, especially at Aoyama Gakuin University, which is known for its fashionable student body. “But the image of women in science is that of someone whose hair is disheveled and who does not care about beauty. Men think you are not cute.”

The widely shared perception that studying science could be the kiss of death for a young Japanese woman’s romantic life is one of several causes behind the low ratio of female students in science and engineering departments.

According to the Ministry of Education, Culture, Sports, Science and Technology, women accounted for 14 percent of the science and engineering students at Japanese universities, even though they represented 43 percent of college students over all, excluding medical and agricultural schools. In the humanities, they make up 66 percent.