The court let stand a lower court decision that the Michigan High School Athletic Association's scheduling discriminates against girls.

As a result, girls basketball will move from fall to winter, and girls volleyball will move from winter to fall.

Michigan is the only state to play volleyball in the winter, and one of two to play girls basketball outside of winter. Hawai'i girls play in the spring.

Michigan's golf, soccer and tennis schedules for both girls and boys also will be altered to more equally distribute the preferable seasons between the sexes.

The MHSAA, the governing body over high school sports, said it was disappointed the Supreme Court didn't hear its appeal.

''Now is the time for our schools to step up and work with the decision of the Court to continue to maximize the quantity and quality of interscholastic athletic participation opportunities for young people in our state,'' the MHSAA said in a statement.

The lawsuit was filed in 1998. Lower courts had ruled in favor of the eventual winners, Communities for Equity, in 2001.

''This is for all the young ladies in Michigan,'' said Diane Madsen, a Grand Rapids mother and one of the original plaintiffs in the suit. ''Some of them don't even realize they are being discriminated against. But now they will have the same opportunities and the same benefits.''

The lawsuit sought to eliminate the practice in Michigan of scheduling the girls' basketball season in the fall and the girls' volleyball season in the winter. Because colleges and high schools in most other states flip-flop those two sports seasons, the suit said Michigan's schedule limits the exposure of the state's female prep athletes and hurts their chances of winning sports scholarships.

The MHSAA said the purpose of having some different athletic seasons for boys and girls is to maximize opportunities for participation.

The MHSAA has said its unique scheduling gives girls teams greater exposure because they don't have to compete for attention with boys games. It has said some schools and conferences don't have enough qualified coaches, game officials or gym space to run girls and boys basketball seasons together in the winter.

Supporters of the season switch say it will help girls beyond sports. They say Michigan's prep scheduling has treated girls like second-class citizens _ affecting their self-image and academics as well as their opportunities in athletics _ without most people in the system even realizing it.