"We're not talking about granting rights and benefits; we're talking about a word.''

So argued Assistant State's Attorney General Jane R. Rosenberg before the state Supreme Court Monday, in seeking to convince the justices that civil unions offer same-sex couples all the same protections and obligations of marriage without the title, "married.''

Attorney Bennett Klein, on behalf of eight same-sex couples who were denied marriage licenses by Madison Town Clerk Dorothy Bean, countered that anything short of marriage is not enough.

"Here the lesbian and gay couples have been relegated to a less prestigious, less advantageous, institution,'' Klein argued.

It will be months before the court rules on whether the institution of marriage in Connecticut must embrace all couples, and not just those comprising one man and one woman.

Marriage is so traditionally rooted in the union of a man and a woman that no appellate court in the nation has yet ruled that same-sex couples have a fundamental right to wed. And if civil unions confer all the same rights and responsibilities, what's the big deal?

Barbara Levine-Rittman answered with an anecdote.

She is one of the plaintiffs, involved in a relationship with Robin Levine-Rittman since 1989. She is a breast cancer survivor who returned to the hospital last month for a screening. Hospital staff said they had to update her information. They asked her marital status. What the heck, Levine-Rittman said she thought to herself, civil unions have been an institution here for 18 months.

"I'm in a civil union,'' she told the staff person. The woman told her that was not an option in her computer, `So I'll just put you in as single,''' Levine-Rittman quoted her as saying.

Plaintiffs Jeffrey Busch and Stephen Davis also were in the courtroom of the Supreme Court Monday. They, too, have been together since 1989, and have a 4-year-old son, Elijah. They have formalized their relationship with a civil union for Elijah's sake, to maximize their benefits as parents, but the ceremony was so unsatisfying neither could recall the exact date.

"Civil unions serve to stigmatize us; they provide second-class status,'' Busch said.

When Elijah cut his eyelid in an accident at school, and Busch rushed him to the hospital, he had to fill out a form that did list "civil union'' as an option. Rather than feeling gratified, Busch felt his privacy had been invaded. "Here this doctor I had never met, who was about to perform an operation on Elijah, was finding out my sexual orientation. It didn't belong.''

All eight same-sex couples walked into the Supreme Court building Monday to hear arguments on whether they should be allowed to marry. They walked away hopeful.

"It seemed like a very open group of justices,'' Joanne "Jodi'' Mock, longtime partner of named plaintiff Elizabeth Kerrigan, said on the steps of the building where their cause will be decided.

The legal issues are multifaceted, and the Gay & Lesbian Advocates & Defenders law firm representing the couples attacked on so many fronts that Justice David M. Borden at one point told Klein he was "riding two horses.''

Borden was referring to Klein's contention that same-sex marriage was both a fundamental right and guaranteed under the sexual anti-discrimination bans of the state constitution.

Klein had argued that under Connecticut's constitution, barring same-sex marriage violates the sex discrimination clause, saying a woman who wants to marry another woman is denied the same right a man has to marry a woman, and vice versa.

Klein also argued that the couples are being discriminated against based on sexual orientation.

But the argument the justices seemed most intrigued by is whether sexual orientation entitles the couples to status as a "suspect class'' of people, entitled to greater protection due to a history of long-term discrimination and political powerlessness.