The Supreme Judicial Court - the same court that legalized gay marriage through a landmark 2003 ruling - heard arguments on a referendum proposed for the 2008 statewide ballot.
Gay marriage proponents told the court that Attorney General Tom Reilly should not have certified the ballot question because the state constitution bars any citizen-initiated amendment that seeks to reverse a judicial ruling.
"The people shouldn't be able to directly attack an SJC decision," said Gary Buseck, legal director of Gay & Lesbian Advocates & Defenders, which filed the lawsuit.
Reilly's office maintains the proposed amendment would not reverse the so-called Goodridge ruling or invalidate existing gay marriages. Instead, if approved by voters, it would amend the state constitution to bar future gay marriages.
The justices took the case under advisement. They did not indicate when they might rule. State lawmakers may also debate the issue in a constitutional convention next week.
After the court made Massachusetts the first state in the nation to legalize gay marriage, opponents saw a ballot question as their best shot at circumventing the ruling.
The ballot question was certified after more than 124,000 signatures were collected, according to the AP.
Before it can be placed on the 2008 ballot, supporters must win the votes of 50 lawmakers - 25 percent of the Legislature - in two successive legislative sessions.
After it turned out that Deputy Prime Minister Andrei Belousov included the Fonbet betting company in the list of backbone enterprises that can count on state support, everyone started talking about these bookmakers.