The court did not allow counties to resume issuing marriage licenses to gay couples while the case is heard.

The move miffed backers of Proposition 8, which was narrowly passed this month as an amendment to the state Constitution that would restrict marriage to heterosexual couples.

The San Francisco Chronicle said the challenge filed after the close vote contended that Prop 8 was such a radical change to the Constitution that it qualified as a "revision" rather than an amendment. An amendment can be passed by a simple majority of the voters, but a revision requires a two-thirds majority.

The court said it would consider whether Prop 8 was a revision or an amendment along with whether it violated separation-of-powers provisions. The justices also agreed to consider what to do about the homosexual couples who were married before Prop 8 passed.

The Sacramento Bee reported Randy Thomasson, president of the Campaign for Children and Families called the challenge "mushy, subjective arguments" and warned of a public backlash if the court voids Prop 8.

"The California Constitution clearly says that the voters have the right to alter the highest law of the land," Thomasson said in a written statement.