SAN FRANCISCO (AP) _ San Francisco politicians voted unanimously Monday to expand the city's domestic partners policy despite congressional pressure that already may have cost the city millions.

The ordinance, which Mayor Willie Brown says he will sign, will make San Francisco the only U.S. city to order private businesses to offer domestic partners any customer discounts they extend to married couples.

Most city businesses that might be subject to the law, such as gyms, car rental companies and insurance agencies, already comply. Still, supervisors are determined that the city set a standard for human rights.

``Banning discrimination is no new concept,'' said County Supervisor Mark Leno, who introduced the measure in June. ``We're talking about inalienable rights here.''

The vote comes despite what gay rights advocates are calling an anti-gay campaign in Washington.

Less than two weeks ago, the House voted 214-212 to block the city from receiving federal housing money because of its year-old Equal Benefits Ordinance, which requires businesses with city contracts to extend health benefits to its workers' partners.

``We should not force or coerce (businesses) to adopt policies they find morally objectionable,'' said Rep. Frank Riggs, R-Calif., who sponsored the measure.

Democrats attacked the Riggs measure as mean-spirited and bigoted, a message meant to promote intolerance. ``I don't know why Mr. Riggs wants to create a war,'' said Rep. Nancy Pelosi, who represents San Francisco.

Still, Monday's expansion of the domestic partner benefits law caused hardly a flutter in the city. It is backed by the San Francisco Chamber of Commerce and the Small Business Network, and has faced little opposition from business owners.

Leno couldn't name a company in the city that would have to change its ways.

``It makes good business sense,'' Leno said. ``It gives business an additional marketing tool and could help them compete with other businesses.''

It's expected to have more impact as a symbolic gesture. Most car rental agencies in the city do not offer special rates to married couples, and some gyms already include domestic partners in its ``family'' categories.

None of the supervisors were concerned about pressure from Washington, said Kieran Flaherty, Leno's spokesman.

``It boils down to, San Francisco values the domestic partner relationship as much as other family relationships,'' Flaherty said.

At 24 Hour Fitness near downtown, where domestic partners already fall under the club's ``couple membership'' category, John Pelletier, got a 50 percent discount two weeks ago because he shares a household with his partner, club member Donald Leighton.

And Laura Gilleran, 23, says she and her live-in girlfriend, T.C. Myers, are more excited by the symbolism of the ordinance than by any discounts.

``It's important, since (gay) marriage is not legal,'' Gilleran said. ``It's important to do what it takes until it becomes such.''