HARRISBURG, Pa.—A proposal to amend the Pennsylvania Constitution to ban gay marriages and civil unions received approval from a Pennsylvania Senate committee March 18 as supporters seek to revive an effort that stalled in 2006.

In a packed hearing, opponents tried, but failed, to delay a vote. The committee’s 10-4 vote, however, was just the first step in the long road to changing the state constitution, which ultimately would require a statewide referendum that could be held no earlier than next year.

Opponents sought to keep the bill in committee for more hearings, if only to clear up the meaning of the amendment’s wording on civil unions and how it could impact the current legal rights of gay and lesbian couples.

Pennsylvania’s 12-year-old “Defense of Marriage” law defines marriage as being between a man and a woman. However, it is silent on the matter of civil unions.

In 2006, the House approved a ban on civil unions, but the proposal died in the Senate.

Opponents of the measure, including advocates for children and victims of domestic violence, have argued that the amendment would prevent same-sex couples and unmarried heterosexual couples from adopting. They also say it would discourage employers from offering domestic-partner benefits.