LANSING (AP) - The Michigan Supreme Court heard arguments yesterday in a lawsuit challenging the Ann Arbor school district's same-sex benefits policy.

But for now, the dispute involves a technicality - not the legality of providing health insurance and other benefits to workers' gay partners.

The case is one of three same-sex benefits cases moving through Michigan's court system. It involves whether 17 taxpayers followed the proper procedure to stop the Ann Arbor Public Schools from offering benefits to gay couples.

The taxpayers are represented by the Thomas More Law Center, a Christian-rights group that says governments and other public employers can't offer benefits to gay couples in future contracts under the Michigan constitution and state law.

But the state appeals court dismissed the Ann Arbor case in 2005 and ruled the taxpayers didn't "demand" that the district stop providing the benefits to employees' gay partners. They had sent letters to school board members asking them to stop the policy.

The appeals court said the letters were merely a request, not a true demand for legal action.

The same-sex benefits issue primarily stems from a 2004 voter-approved constitutional amendment making the union between a man and a woman the only agreement recognized as a marriage "or similar union for any purpose."

The appeals court, which heard arguments over the constitutionality of same-sex benefits in April, could rule in that case soon. Also, an Ingham County judge earlier this month dismissed a separate challenge to same-sex benefits at Michigan State University, ruling the plaintiffs had no standing to sue.