A gay couple challenging Proposition 8 in federal court Monday said civil unions and domestic partnerships aren't the same as marriages, something they view as a stepping stone toward starting a family, CNN reported.

"[It's] like putting a Twinkie at the end of a treadmill and saying, 'You can only have a bite,' " testified Paul Katami, one of the plaintiffs. "And you want the whole thing. ... All I want is to be married."

Katami and his partner, Jeffrey Zarrillo, are among plaintiffs asking Chief Judge Vaughn R. Walker of the U.S. District Court in San Francisco to issue an injunction against the enforcement of California's Proposition 8, arguing the ban on same-sex marriage is unconstitutional.

If allowed to marry his partner, 36-year-old Zarrillo said he would finally feel equal and complete.

"I'd be able to stand there as one family, as a married individual," Zarrillo said, noting the "pride that one feels when that happens."

About 100 protesters against the measure and in favor of same-sex marriage gathered peacefully outside the courthouse before the hearing, waving signs supporting equal rights.

The case will likely head to the U.S. Supreme Court no matter the outcome. It is expected to set legal precedents that will shape society for years and result in a landmark court decision that settles whether Americans can marry people of the same sex.