WASHINGTON -- The Bush administration defended a 30-year-old federal law that has greatly expanded women's athletic programs, arguing Wednesday that a lawsuit by male college coaches and athletes should be thrown out.

The lawsuit, filed in January in federal district court by the National Wrestling Coaches Association, says the law -- meant to ensure equal educational and athletic opportunities for men and women -- instead hurts lower-profile male sports.

The 1972 statute known as Title IX prohibits any school or college that receives federal funding from discrimination based on sex in sports or academics.

Because nearly all schools receive some federal aid, women have gained the opportunity to play many more sports under Title IX. But hundreds of men's sports programs have been cut nationwide, with Title IX often cited as the reason. Sports such as wrestling, swimming and track and field have been hit particularly hard.

Federal regulations say schools can comply with Title IX by showing that opportunities for women are "substantially proportionate'' to their enrollment, correspond to the level of students' interest, or are being increased through the addition of new teams.

The suit against the Education Department contends that many colleges and universities have trimmed men's sports -- rather than adding women's teams -- to achieve equality.

Numerous lawsuits have been unsuccessfully brought against individual schools for such decisions. The NWCA suit challenges the federal rules themselves, asking the court to force new rules that define compliance as providing opportunities for female athletes based on interest, instead of enrollment.

In its response, the government said the suit should be dismissed because only the individual schools can right the wrongs the groups claim have been committed. Even if that were not so, the department argued, federal law governing how agencies can be sued and an expired six-year statute of limitations preclude the suit.

"Plaintiffs have not and cannot demonstrate any likelihood that a favorable judgment in this action would have any substantial impact on decisions by educational institutions regarding which sports to include in their athletic programs,'' said the brief filed by Justice Department lawyers on the Education Department's behalf.

NWCA Executive Director Mike Moyer dismissed the government's filing.

"We don't believe it in any way diminishes the strength of our position,'' he said. "We're going to remain very confident that we're going to restore Title IX to its original intent.''

Supporters of Title IX agree that women's opportunities shouldn't be increased by restricting men's. But they say the fault lies not with the law, but with universities that choose to eliminate entire teams rather than cutting idle players or dollars from popular sports such as football and basketball.

The National Women's Law Center cites studies that have shown that the majority of schools come into compliance without cutting men's teams or relying on comparisons to enrollment, and that men's participation in athletics has increased as well as women's.

A reply from the NWCA is due by June 10.