San Francisco , California ( CNN ) -- A gay couple challenging Proposition 8 in federal court Monday said civil unions and domestic partnerships are n't the same as marriages , something they view as a stepping stone toward starting a family . `` [ 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 . '' During testimony , attorney David Boies asked Zarrillo why he believed marriage was a better option for same-sex couples when compared with domestic partnerships and other arrangements states have for same-sex couples . `` Domestic partnership would relegate me to second-class citizenship , maybe third-class -- and that 's not enough , '' he said . Zarrillo and Katami of Los Angeles , California , are joined by Kristin Perry and Sandra Stier of Berkeley , California , in the court challenge . Zarrillo said he believes it 's an important step to be married before having children , saying it would make it easier for the couple and the child and would afford the child additional protections . Being married and wearing a wedding ring sends a message to society , he said . `` It says to them , these individuals are serious , '' Zarrillo said . `` They 're committed to one another . '' Another attorney for the couples , Theodore Olson , argued to the judge that a ban on Proposition 8 leaves gay couples out of something available to all other people in the United States . `` Marriage is central to life in America , '' Olson said . `` It promotes mental , physical and emotional self . It 's the building block of family , neighborhoods and community in our society . '' Proposition 8 , Olson said , ended the dream of marriage for same-sex couples , which includes hundreds of thousands of Californians . The state , he said , `` has put people into categories . '' `` You 're different , and we 're going to take away that right from you , '' Olson said , interpreting the meaning of the ban . `` ... That 's discrimination . '' However , Charles Cooper , an attorney representing Protect Marriage , the group that came up with Proposition 8 , told the judge in his opening statement the purpose of marriage is to promote procreation between men and women . Same-sex marriage `` will likely lead to very real social harm ; it 's too novel and experimental , '' he argued . Californians `` are entitled to make this critical decision for themselves , '' he said , pointing to voter support of the proposition . Except for the issue of marriage , gays and lesbians have been successful in attaining policy goals , Cooper said , adding that California has some of the most comprehensive protections in the nation . 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 . In legal circles and across the Internet , it has been dubbed this generation 's Brown v. Board of Education , the case that led to the Supreme Court decision that outlawed segregation in schools . Some say it could be the biggest ruling since Roe v. Wade , which tackled abortion . It also closely echoes the Supreme Court case that overturned bans on interracial marriage . CNN 's Mallory Simon and Bill Mears contributed to this report .
The man testifies partnerships , unions only a part of what everyone else gets . ' Katami : ` ` You want the whole world . ... All I want is to be married . '' Lawyer for ban : Gay marriage has ` ` very real social problem ; it 's too novel and experimental '' Lawyer for gay couples : California ban ` ` has sent people into depression ''