Millions of Americans are being encouraged to skip work today and refuse to spend money on any goods or services — at an estimated cost of $2 billion to the US economy — in a nationwide boycott being touted as “Day Without a Gay”.

The event, which encourages gays and lesbians to “call in gay” rather than calling in sick has been orchestrated by activists in California to protest against the adoption of Proposition 8 in the state, which banned same-sex marriages.

The proposition, predicted by the polls to fail, was voted into law thanks mainly to a get-out-the-vote drive by the Mormon Church. It is expected to be challenged in the courts.

Although there are few reliable statistics on the number of gays and lesbians in the US estimates have ranged from 2.8 per cent of the population in a report by the Centres for Disease Control and Prevention in 2002, to 10 per cent from research conducted by Alfred Kinsey, a biologist, in the 1950s.

Witeck-Combs Communications, a PR company in Washington which specialises in the “pink dollar”, published a study this year estimating that gays and lesbians spent about $700 billion (£475 billion) in America each year.

Bob Witeck, the chief executive, said that it would be difficult to measure the success of the boycott because gays and lesbians work in so many fields. He added that rather than halting all consumer spending for the day supporters would have a bigger impact if they devoted their money to gay-friendly businesses.

“Our community leaders who are running bookstores, newspapers, flower shops, coffee houses, bars and many, many other things are hurting right now, so paying attention to their needs during this hard time is an effective form of activism,” he said.

Sean Hetherington, a comedian and personal trainer from West Hollywood who came up with the idea of a boycott with his boyfriend, Aaron Hartzler, said that he was encouraging gays and lesbians to do community work instead of staying at home.

“You can take away from the economy and give back in other ways,” said Mr Hetherington, 30, who will spend today volunteering at a school.

The website daywithoutagay.org, which the couple run, states that on “December 10, 2008 the gay community will take a historic stance against hatred by donating love to a variety of different causes”. It lists potential volunteering jobs at non-profit agencies.

Despite his efforts some activists argue that “calling in gay” could be impractical and counter-productive.

“It's extra-challenging for people to think about taking off work as a form of protest, given that we are talking about people who may not be ‘out' at work, and given the current economic situation and job market,” Jules Graves, 38, a co-ordinator of the Colorado Queer Straight Alliance, said. “There is really not any assurance that employers would appreciate it for what it is.”

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