SALEM - A bill that would give more women insurance coverage for prescription birth control won Senate approval Wednesday despite arguments by Republican lawmakers that the measure is unnecessary and would be too expensive.

Senate Majority Leader Kate Brown, D-Portland, the bill's chief sponsor, said that requiring insurance companies to cover prescription birth control at the same level as other prescription medicines is an "issue of basic fairness and equity."

The bill passed 20-7, with most Republicans opposed. The measure goes to the Republican-controlled House, where similar bills have failed in previous sessions.

A similar bill pending in House this session has not yet been discussed.

Brown also said it will bring the state in line with a federal ruling in 2000, which said employers who did not cover contraceptives were violating federal civil rights laws.

The bill's foes say the federal ruling makes Oregon's bill unneeded because anyone with insurance who wants prescription contraception coverage already has legal ground to demand it.

"Those who do not have it are those who request not to have it," said Sen. Jeff Kruse, R-Roseburg, of women who do not currently have prescription contraceptives covered.

"We're better off just staying with the federal policy," Kruse said.

About 50 percent of insurance companies cover birth control in Oregon, according to a 2001 study of more than 1,700 women by the state Department of Human Services.

Brown said current state law puts Oregon businesses in a "legal quagmire" because it allows businesses to purchase insurance plans without knowing they may be violating federal policy.

Sen. Alan Bates, D-Ashland, said that the bill would protect businesses from being sued in federal court by employees who do not receive birth control coverage.

Bates, a doctor, also said he frequently sees women patients who do not have coverage for prescription contraception, and it's difficult to explain why vasectomies for men, or more complicated birth-control procedures, are covered while pills are not.