Economists testifying in the U.S. District Court case challenging Proposition 8, the California referendum that banned gay marriage in the state, said the policy will cost the state $490 million over the next three years, $37.2 million of that in San Francisco alone. But other economists say those estimates, based on income from gay weddings and related expenses, are only a tiny fraction of local and state economies. They also say it’s hard to know how many gay couples would marry if the rule were overturned. But the experts defended their testimony. One said the benefits of marriage to individual people and households are hard to measure, but are still “extremely powerful.” Another noted that income from gay marriages "might not solve the entire budget crisis, but for given agencies or universities or school systems, the amount of money we're talking about is quite meaningful."