In all, Ms. Xiong said, about 20 people around China -- mostly women but some sympathetic men, too -- shaved their heads to protest the rules. Their protest was inspired by three female artists who shaved their heads in public here in March to call for greater women's rights.

"The Education Ministry's response made us really angry -- it's just such a pity," Ms. Xiong said in an interview in Beijing, her normally shoulder-length hair reduced to stubble. "It's illegal too. The Education Law forbids discrimination on several grounds including gender. And the Education Ministry is allowing it."

No one is quite sure when gender quotas and gender-based admission scores were first implemented; but by now, they appear to be deeply entrenched, according to Chinese news reports that published publicly available admission criteria for the gaokao, the nationwide university entrance exam, as evidence. Several of the universities in question, including the University of International Relations, declined to respond to requests for information, referring queries to the college's propaganda or international affairs offices, which did not respond.

An official who answered the telephone at the Teaching Office at the China University of Political Science and Law said the school did not have gender-based enrollment policies. For criminology, she said, "female students must account for less than 15 percent of students because of the nature of their future career," but women were scoring so well that in practice a higher percentage were being admitted. She declined to give her name and did not elaborate on her comment.

The practice began at least as early as 2005, according to Chinese news reports, and was in response to the rising numbers of women getting into universities, where they are starting to outstrip men in some areas, especially languages.

In 2004, women made up 43.8 percent of undergraduate students, rising to 49.6 by 2012, according to Education Ministry figures cited by The 21st Century Business Herald.

In master's programs, women made up 44.1 percent of students in 2004, rising to 50.3 by 2010. Among doctoral candidates in 2010, however, just over 35.4 percent were women, up from 31.3 in 2004.

In July, the Southern Metropolis Daily, a newspaper in Guangzhou, said the practice of discriminating in admissions was "extremely clear," calling it "the male-female difference."

"In science courses at the China University of Political Science and Law, the bar is at 632 points for women but 588 for men," the newspaper said, providing other similar examples from other colleges.

The practice was especially entrenched at police or military-affiliated universities, it noted. It was also common at language schools.

It was reported in July that the Shanghai International Studies University had lowered the bar of entry for male applicants to language programs in Hebrew, Arabic, Ukrainian, Korean and Russian.

University administrators "believe that Arab nations don't want to deal with women," Ms. Xiong said. "So they make it harder for women to get in to study Arabic," a language that is not commonly studied in China.

The reports led Lu Pin, a program manager at the Media Monitor for Women Network, to join with a lawyer, Huang Yizhi, to file an "open information" request with the Education Ministry.

"Comrade Lu Pin," the ministry responded on Aug. 22. "In view of considerations of national interest," to meet personnel training needs in some job areas or specialties, "a few colleges may appropriately adjust the enrollment ratios of men and women." It ended with a friendly salutation: "Thank you for your support of the open government information work of the Education Ministry!"

The rules affected students like Ouyang Le, according to Ms. Xiong. A fresh graduate from a Guangzhou high school, Ms. Ouyang had wanted to study at the University of International Relations. She scored 614 points on the gaokao, but as a woman, needed 628. If Ms. Ouyang had been a man, she would have needed just 609.

Ms. Xiong said Ms. Ouyang, who contacted the activists to recount her story, was a rare case -- most young women do not speak up, instead silently switching their major or university. "They are so young and inexperienced, and then their parents often advise them not to make trouble," Ms. Xiong said.

She added that it was difficult to know how many women were affected every year but that the number could run in the hundreds or thousands.

Feminists are deeply worried by the trend.

"Young women today have real opportunities to study, and that they are becoming so outstanding is really to their credit, their families' credit and to the country's credit," said Ms. Lu, the Media Monitor program monitor. "They worked so hard to get these high grades. And we cannot accept that the Education Ministry is infringing on their rights. They must respect their own laws."

Dissatisfied with the ministry response, which they said was "very vague," Ms. Lu and Ms. Huang have filed a second request for information, asking what constitutes "national interest," and what are the "special subjects" that give grounds for gender discrimination.

The issue is much discussed on campuses, where women in some arts faculties in particular may heavily outnumber men, making up to 70 percent of students in some classes.

But women still lag in many science programs, where there are not similar efforts made to increase their numbers with weighted admissions standards.

At a school specializing in rocket and aviation research at the Beijing Institute of Technology, women made up 13.8 percent of students in 2008, rising to 16.4 in 2011, The 21st Century Business Herald reported.

In the news media, the phenomenon increasingly is being called the "kingdom of women" or the "detachment of women," using military terminology.

He Qin, the deputy chairman of the Students' Union at the School of Foreign Languages at Huazhong Agricultural University in Hubei Province, said the lack of men studying languages caused practical problems, the newspaper reported. At the beginning of the semester, new female students arrive "one after another," Mr. He was quoted as saying.

"We have to lead the way to their dormitory, and due to not enough manpower they have to carry their suitcases to the sixth floor," he added. "The hands are sore to the point of losing consciousness."

Yang Jianxiong, one of 13 male students in his class at the School of Plant Science at the university, said he felt "humiliated" at the rising number of female students, the newspaper reported.

This year, the school enrolled 442 students, of whom 238 were women, or 54 percent.

"Boys are now inferior to girls in terms of both number and scores," Mr. Yang said. "Girls win the majority of scholarships and praise each year."

Women's higher admissions rates may be all the more remarkable since in China, 118 boys are born for every 100 girls -- by a simple law of averages, more boys should be getting in. But under the country's one-child policy, single girls are getting the attention and support that once only their brothers did, accounting for their catch-up, experts say. The skewed gender ratio at birth shows a strong cultural preference for boys and indicates how far Chinese women have triumphed against traditional discrimination, including in education.

Tang Shangshu, a counselor at the School of Plant Sciences, said that relatively speaking, boys matured later, while girls had better study habits, the 21st Century Business Herald reported.

In addition, Mr. Tang said that many jobs that once required physical labor had been replaced by labor-saving science and technologies. That had removed women's physical disadvantage, while "in terms of wisdom boys may not have particularly obvious advantages," Mr. Tang told the newspaper.