Always remember that it's hard to win a referendum. People who don't care about an issue one way or another tend to vote "no". It shows how strongly the public opposes same sex marriage that initiatives to ban it pass by such wide margins. Also, abortion is an issue where it's easier for the left to blur things ("What if a girl has been raped by her uncle who has AIDS?", etc.), and the blurring leads to people voting "no" as a cautionary measure.
Hopefully 73 will pass.
(Denny Crane: "I Don't Want To Socialize With A Pinko Liberal Democrat Commie.Say What You Like About Republicans. We Stick To Our Convictions. Even When We Know We're Dead Wrong.")
Evidently, it's a sacrament in California.