SAN FRANCISCO, California (CNN) -- The California Supreme Court has cleared the way for Californians to vote in November on whether to ban same-sex marriages in the state.
A gay couple is married in California in June. Voters could void same-sex marriages in the state in November.
The court on Wednesday denied a petition to remove the initiative from the state's general election ballots. The unanimous decision was handed down without elaboration.
Hundreds of marriage licenses have been issued to same-sex couples since mid-June, a month after the court overturned the state's laws against such unions.
However, on June 2, opponents of same-sex marriage filed for a ballot initiative that would ban such marriages in the state's constitution. Such a ban would overturn the court's May ruling.
Equality California, a Sacramento-based activist group, filed a petition against the initiative -- Proposition 8 -- arguing that it involves a constitutional revision that can't be adopted through a ballot vote.
The group also contended that petitions circulated to qualify the proposition for the ballot contained material that misled readers about the measure's effects.
Jennifer Kerns, a spokeswoman for the proposition, called Wednesday's decision "a huge victory."
"We believe it deals a strong blow to our opponents and sends a strong message that they won't be able to keep the ballot initiative away from the people of California," she said.
Calls Wednesday to Equality California were not immediately returned.
If the proposition is approved, it would be the second time same-sex marriages have been voided in California.
In February 2004, San Francisco Mayor Gavin Newsom -- who is considering a run for governor -- challenged the state's laws against same-sex marriage, ordering city officials to issue marriage licenses to gay and lesbian couples.
Those unions were voided by the California Supreme Court, though the justices sidestepped the issue of whether banning same-sex marriage was unconstitutional, allowing legal cases to work their way through the lower courts.
Several gay and lesbian couples -- along with the city of San Francisco and gay-rights groups -- sued, saying they were victims of unlawful discrimination.
A lower court ruled San Francisco had acted unlawfully in issuing marriage licenses to same-sex couples. However, the state Supreme Court's ruling in May struck down the state's ban on same-sex marriage as unconstitutional.
That decision made California the nation's second state, after Massachusetts, to legalize same-sex marriage. Four other states allow civil unions.