OLYMPIA, WASH. ? Gov. Chris Gregoire signed a gay civil rights bill into law Tuesday, though the law may be held in limbo if opponents are successful in forcing a referendum.

The measure adds “sexual orientation” to the law that bans discrimination in housing, employment, insurance and credit.

The amendment, passed by the Legislature on Friday, makes Washington the 17th state to pass a law covering gays and lesbians, and the seventh to protect transgender people.

The law is scheduled to take effect in June, 90 days after the end of the Legislature’s session.

However, it would be frozen until a November vote if opponent Tim Eyman gets enough signatures by the June 7 deadline for a referendum.

In addition to seeking to remove “sexual orientation” from the law, Eyman is pushing an initiative that would prohibit state government from requiring preferential treatment for any person or group “based on sexual orientation or sexual preference.”