Same-sex couples Paul Katami (L), Jeff Zarillo (2nd L), and Kris Perry (2nd R) and Sandy Stier pose for photographs before the start of their trial in San Francisco, California January 11, 2010. California's ban on gay marriage goes to trial on Monday in a federal case that plaintiffs hope to take all the way to the US Supreme Court and overturn bans throughout the nation. [Agencies]