SAN FRANCISCO (AP) _ Businesses offering discounts and other deals to married couples would be required to extend them to domestic partners, including gay couples, under a proposed city law that goes to a final vote today.

The first-of-its-kind ordinance would affect a variety of private businesses _ including gyms, car rental companies and insurance agencies.

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

Businesses that have contracts with the city already are required to provide their workers' gay and straight domestic partners with benefits under San Francisco's year-old equal-benefits ordinance. The new legislation doesn't force other private businesses to change their worker benefits, only their policy on customer discounts to couples.

The proposal won the Board of Supervisors' unanimous approval last week. It needs a second vote from the board today and the OK of Mayor Willie Brown, who is expected to sign it.

The plan, which has faced little opposition from business owners, would be more symbolic than practical in many cases.

Most car rental agencies, for example, do not offer special rates to married couples, and some gyms already include domestic partners in its ``family'' categories. And at businesses like 24 Hour Fitness near City Hall, domestic partners already fall under the club's ``couple membership'' category.

Still, Laura Gilleran, 23, says she and her live-in girlfriend, T.C. Myers, are excited by the ordinance.

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