Amends California Constitution to provide that a marriage between one man and one woman is the only legal union that shall be valid or recognized in California. Bars domestic partnerships from being valid or recognized as legal unions in California. Eliminates certain rights and obligation conferred by California law on same-sex and heterosexual couples registered as domestic partners, concerning subject areas including, but not limited to, community property, intestate succession, stepparent adoption, child custody/support, hospital visitation, healthcare decisions for an incapacitated partner, insurance benefits, and recovery for wrongful death. Summary of estimate by Legislative Analyst and Director of Finance of fiscal impact on state a...