A landmark gender-equity law protects whistleblowers who accuse academic institutions of sex discrimination, the Supreme Court said Tuesday, ruling that coaches and teachers may sue for retaliation if they are fired for complaining on behalf of others.

The 5-4 decision sides with Alabama high school coach Roderick Jackson (search), who said his girls' basketball team received worse treatment than the boys' team. It is a victory for women's advocates who say the legal protection will prompt reports of bias that would otherwise go unsaid or unheeded.

Congress intended to allow whistleblower suits when it passed the Title IX (search) law, justices said.

"The text of Title IX prohibits a funding recipient from retaliation against a person who speaks out against sex discrimination, because such retaliation is intentional discrimination on the basis of sex," Justice Sandra Day O'Connor (search) wrote for the majority.

She was joined in her opinion by Justices John Paul Stevens, David H. Souter, Ruth Bader Ginsburg and Stephen G. Breyer.

The 1972 law, best known for promoting women's athletics, bars sex discrimination in any educational program receiving federal funds. It already was settled law that students or others could sue if they thought they were shortchanged based on their sex.

But the statute has been silent as to the rights of whistleblowers — regardless of gender — who aren't direct victims of discrimination but who claim retaliation. Since 1975, the federal government has interpreted Title IX to cover retaliation claims.

Justice Clarence Thomas (search) was among the four dissenters.

Whistleblowers shouldn't be given protection unless Congress explicitly says so, said Thomas and three other justices who voted no. They noted that other civil rights laws have specific provisions addressing retaliation.

"We require Congress to speak unambiguously in imposing conditions on funding recipients through its spending power," Thomas wrote.

Under the ruling, schools now may be forced to pay compensatory and punitive damages for retaliation claims, something that was never contemplated when they chose to accept federal funding, the dissenting justices said.

Jackson lost his coaching job in 2001 after repeatedly asking Birmingham school officials to provide his team a regulation-size gym with basketball rims that weren't bent — just like the boys' team had. He then sued under Title IX, claiming wrongful termination.

The lower courts disagreed and threw out his lawsuit, ruling that Title IX did not authorize retaliation claims. The Supreme Court's ruling now allows Jackson to proceed to trial to prove he was suspended because of his complaints.

"To prevail on the merits, Jackson will have to prove that the board retaliated against him because he complained of sex discrimination," O'Connor wrote in the majority opinion.

His case had drawn wide interest, with support from a coalition of 180 civil rights groups including the NAACP (search), the American Civil Liberties Union (search) and the American Federation of Teachers (search), as well as dozens of women's advocacy groups.

Opposing Jackson were the National School Boards Association (search) as well as nine states — Alabama, Delaware, Hawaii, Nevada, Oregon, South Dakota, Tennessee, Utah and Virginia, which argued that allowing retaliation claims would unfairly open the door to a flood of litigation.

Jackson, who remained on the payroll as a teacher, eventually was rehired as coach in 2003 on an interim basis, and the old gym now has two new, regulation-sized hoops.

The case is Jackson v. Birmingham Board of Education, 02-1672.