After nearly 30 years of operation a law requiring equal opportunity in sports for women in the United States has led to a rise in the number of women athletes, according to a government study.
But there has been a second, unanticipated impact: fewer opportunities for men.
The study, by the General Accounting Office - the investigative arm of Congress - backs complaints that universities have cut sports for men to expand opportunities for women in response to the so-called Title IX rules barring discrimination at institutions that receive federal aid.
It comes as Title IX is being singled out for the success of the US women's soccer team and for extraordinary popular interest in this summer's Women's World Cup. More than 600,000 people attended the games, which were held in several US cities.
Passed in 1972, Title IX prohibits gender discrimination in all public primary and secondary schools and public universities. Almost all private universities and colleges are also covered because they receive federal funding in the form of student financial aid programmes.
The law requires that such schools offer opportunities for men and women to play intercollegiate sports at rates "substantially proportionate" to their enrolment. If half the students at a school are women, women should account for half the athletes.
Some universities have tried to reach this balance not by adding women's teams, but by eliminating men's. A few have cut expensive men's sports such as American football in favor of cheaper women's teams that involve larger numbers of participants.
The GAO study found that the number of female undergraduate athletes rose 16 per cent since 1985, the number of women's teams increased by 17 per cent, and the number of athletic scholarships available for women rose 66 per cent. The number of universities with highly competitive women's soccer teams alone has more than doubled in the 1990s.
But the number of male undergraduate athletes fell 12 per cent since 1985, and the number of men's teams decreased by 3 per cent. The number of university wrestling programmes has fallen from about 700 before Title IX to about 300 today, for instance.
Thirty-one universities have cut their men's golf teams. The University of California at Los Angeles has dropped its world-renowned men's swimming, water polo and gymnastics teams, which had produced Olympic gold-medal athletes.
Overall participation rates are considerably higher for men than for women, the GAO found. About 10 per cent of male undergraduates play sports, compared with 5 per cent of women students. In high-school sports, boys still outnumber girls by a two-to-one margin.
Other studies have shown that men's teams still get 80 per cent of university athletic budgets, and 84 per cent of athletic scholarships continue to go to men.