Prop. 8 would change the state constitution and take away the right of same-sex couples to marry.
It has generated enormous enthusiasm from people on both sides of the issue.
Sunday, those in favor of Prop. 8 rallied in Cupertino.
"What's at stake, you know, children deserve to have both a mom and a dad," Prop. 8 supporter Ron Prentice said. "And there's absolutely no research that says same-sex are better or as good as parents to children and kids need the complimentary of a mom and a dad."
Meanwhile, some Bay Area pastors urged their congregations to vote "no," calling it a clear act of discrimination.
"This is about inclusion and not leaving people out of our families and not leaving people out of our communities," Andrea Shorter said. "It has been the legacy of our community and our movement to stand against discrimination."
Other religious groups, including the Catholic and Mormon churches are in favor of the proposition.