Opponents claim the referendum was illegal, because it put two issues to voters at the same time: to ban gay marriage and if the state should outlaw civil unions.
Supporters of the ban feel it's about only one topic. The first part was about the definition of marriage.
"The second part of it was whether or not we're going to protect the institution of marriage," said Julaine Appling of Wisconsin Family Council. "Really, if we didn't have the second part of that, the first part is of very little value because then you can have marriage by another name, call it domestic partner, callit a civil union , call it whatever you want. But it is marriage by another name."
Opponents to the ban feel some voters were left to answer only once for two questions.
"Believe it or not, calling it something different than marriage matters to people," said Glenn Carlson of Fair Wisconsin. "20% difference between people who are opposed to civil unions and people who are opposed to marriage -- that 20% of the population essentially got disenfranchised by having to vote on both of those things at the same time."
The court agreed to hear the case on a referendum that was approved by around 60 percent of voters in november of 2006.
A political science instructor recently challenged a Dane County judge's dismissal of the case last year.
Last month, the Madison-based district 4 court of appeals asked the high court to take the case immediately because of its statewide significance.
No word on exactly when the case will be heard.