The Wisconsin Supreme Court ruled Wednesday that the state's constitutional ban on gay marriage is valid, the AP reported.

In a 7-0 ruling certain to disappoint gay rights advocates, the court disagreed with the argument that the ban – approved by 60% of voters in 2006 – was not valid because the referendum illegally asked voters to decide on two subjects simultaneously.

The question asked voters to decide whether marriage should be limited to a heterosexual union and whether to outlaw any “legal status identical or substantially similar” to marriage for gay and lesbian couples.

In writing the ruling for the majority, Justice Michael Gableman said the amendment is valid because both parts of the question “carry out the same general purpose of preserving the legal status of marriage in Wisconsin as between only one man and one woman.”

William McConkey, a University of Wisconsin-Oshkosh political science professor, filed the lawsuit.

Plaintiffs appealed their case to the District 4 Court of Appeals after being dismissed by a lower court. The appeals court asked the Wisconsin Supreme Court to review the case, saying “the validity of the marriage amendment is a matter of significant public interest with statewide implications.”

In defending the amendment, Wisconsin Attorney General John Byron “J.B.” Van Hollen called it the “will of the people.”

Van Hollen, a Republican who is eyeing a 2010 run for governor, stirred controversy last year when he declined to defend the state's gay-inclusive domestic partnership registry, calling it unconstitutional. Social conservatives have mounted a legal challenge to the law that gives gay and lesbian couples access to 43 rights, most of which center around estate planning and hospital visitation issues.