Honolulu ? Hawaii, the state that adopted the nation’s first “defense of marriage” constitutional amendment a decade ago, has now become the latest battleground in the fight for same-sex civil unions.

It would become the fifth state to legalize the alternative to gay marriage if the Democrat-dominated Legislature and Republican governor approve a civil union law. The measure was passed by the state House this month but it now faces the Senate, where a divided committee is to vote Tuesday.

Republican Gov. Linda Lingle has declined to comment on the issue, and it’s unclear whether she would veto the bill.

Gay-rights organizations argue that civil unions would promote basic equality in the nation’s most ethnically diverse state, but opponents fear the erosion of an island culture that values conventional family ties.

“Society in general is becoming more accepting,” said Suzanne King, a real estate office manager who is raising her 9-year-old daughter, Shylar Young, with her partner of nearly 28 years, Tambry Young. “It’s not unusual to come upon a gay family. There isn’t this fear that by giving us rights, it’s going to reduce the traditional family.”

King and Young said they want a civil union law so gay couples can more easily adopt children, share health benefits and gain hospital visitation rights. They plan to enter into a civil union if the measure becomes law.