SAN FRANCISCO (AP) — Sealing his reputation as one of the nation’s most gay-friendly governors, California Gov. Gray Davis has signed a domestic partner bill granting same-sex couples nearly all the same rights and responsibilities as married spouses.

California already had strong domestic-partner laws, but the bill Davis signed at San Francisco’s Gay, Lesbian, Bisexual and Transgender center was designed to close the legal gap, to the extent possible under federal law, that separates gay and straight couples.

The bill expands the rights of gay couples in areas ranging from health coverage and parental status to property ownership and funeral arrangements. It gives both partners in a relationship equal status as parents if they have or adopt a child together, and allows them to seek child support and alimony.

It includes the right for people registered as domestic partners to be covered under each other’s car insurance plan, to take extended leave from work to care for a partner, and exempts them from estate and gift taxes. After a partner’s death, they would have the authority to consent to an autopsy, donate organs or make funeral arrangements.

The bill also prevents courts from forcing a domestic partner to testify against the other partner in a trial.

The bill, by Assemblywoman Jackie Goldberg, a Democrat from Los Angeles, also places greater legal responsibilities on domestic partners. For instance, they would be responsible for their partner’s debts.

The law won’t take effect until January 1, 2005, giving couples who don’t want such commitments time to opt out by withdrawing their registration as domestic partners.

National gay rights advocates say the legislation puts the state on just about the same footing as Vermont, which has been considered the most gay-friendly in the nation since it created a system of civil unions for same-sex couples.

The main legal difference is that California same-sex couples still won’t be able to file their state income taxes jointly, as is possible in Vermont. State lawmakers here feared that conflicting tax codes would make same-sex households more subject to federal tax audits, said Shannon Minter, legal director of the National Center for Lesbian Rights in San Francisco.

There’s an important symbolic difference as well — in Vermont, couples must have their civil unions solemnized or certified in a civil ceremony, while in California, domestic partners merely register with the state by turning in notarized applications with a $10 fee.

In addition, participants in Vermont’s civil unions are legally called “spouses.” Some California politicians consciously wanted to avoid making the domestic partner bill directly challenge “marriage” as an institution.

“There are some ways in which the Vermont statute provides slightly more equal treatment,” Minter said.

Davis has worked hard to solidify his image as a champion of gay rights, especially since the recall campaign began. And he appears not to fear much of a backlash — a recent Field Poll found 72 percent of California voters surveyed supported expanded rights for same-sex couples.

In 1999, California became the first state in the country to allow gay and lesbian couples, as well as elderly heterosexual couples, to register as domestic partners. Since then more than 22,000 couples have signed up with the secretary of state.

Two years ago, the legislature passed a measure giving domestic partners about a dozen rights, including the right to make medical decisions for incapacitated partners, to sue for a partner’s wrongful death and to adopt a partner’s child.