By a 10-4 vote, the Senate Judiciary Committee yesterday advanced a bill to amend the constitution to ban same-sex marriage or civil unions.

The bill now goes to the Appropriations Committee before consideration by the full Senate.

It would have to be passed by the General Assembly in two consecutive sessions and then approved by voters in a referendum.

The amendment would read, "No union other than a marriage between one man and one woman shall be valid or recognized as marriage or the functional equivalent of marriage by the commonwealth."

The committee vote yesterday came over the objections of a minority of senators who said the language was discriminatory and confusing, and could jeopardize existing domestic-partner benefit programs offered by the Cities of Philadelphia and Pittsburgh and elsewhere.

Proponents say they believe an amendment is the only way to protect traditional marriage from court challenges that led to the legalization of same-sex marriage in Massachusetts and civil unions in Vermont.

There have been no challenges to the Pennsylvania Defense of Marriage Act, which defines marriage as a union between a man and a woman, since its passage in 1996. But opponents say that if the Constitution is amended, it will open the door to discrimination lawsuits by same-sex or unmarried couples who are denied benefits.

Judiciary Committee Chairman Stewart Greenleaf (R., Bucks) and Sen. John Gordner (R., Columbia) said they did not believe the amendment would eliminate access to existing benefits or other legal rights of same-sex couples or unmarried partners.

"This will protect the sanctity of marriage and ensure that benefits are preserved," said Gordner, adding that 27 states had amended their constitutions to ban same-sex marriage.

Sen. Jay Costa Jr., a Democrat from Pittsburgh, which offers its city employees domestic-partner benefits, disagreed.

He said the Pittsburgh ordinance uses the term functional equivalent of marriage as a way to assess those seeking domestic-partner benefits - the same language that would be used to disqualify people from recognition in the bill's amendment language.

"Those people would be harmed," he said.

Larry Frankel, state legislative counsel for the American Civil Liberties Union, said domestic-partner benefit programs in any municipality or at public universities would be open to court challenge and that couples moving from other states such as New Jersey, which recognizes civil unions, would not have legal standing.

"A court could bar the state or a local government from offering domestic-partner benefits if it believed that offering such benefits would be recognizing a union that is the functional equivalent of marriage," said Frankel.

Diane Gramley, president of the American Family Association of Pennsylvania, applauded the vote as "pro-family."

"Health care, property-tax relief or graduation tests are not important if society does not have a stable foundation," she said.

Stacey Sobel, executive director of Equality Advocates of Pennsylvania, said she believes all families deserve a stable foundation.

"The commonwealth should not create laws that protect only some of the families," she said.

In 2006, the House and Senate passed versions of a marriage amendment but could not agree on the language. The bill was reintroduced this session by Sen. Michael Brubaker (R., Lancaster).

See how members of the committee voted at http://go.philly.com/amendment