Seattle ? Same-sex couples cannot be deprived of the right to legally marry in Washington state, a judge ruled Wednesday in a decision hailed as a powerful affirmation of equal rights for gay couples.

While significant, the decision does not immediately clear the way for Massachusetts-style gay weddings in Washington state. The state Supreme Court must first review the case before same-sex marriage licenses can be issued. The court could take months to hear the case.

Still, gay couples said they were thrilled by the ruling and expressed confidence that they would prevail whenever the high court makes its decision.

“We, all of us, are absolutely overjoyed today,” said Johanna Bender, alongside her partner, Sherri Kokx. “We’re fully confident that the Supreme Court will uphold this decision.”

King County Superior Court Judge William L. Downing ruled in favor of gay couples who argued that Washington’s law restricting marriage to one man and one woman violated the state constitution. In his decision, Downing singled out critics who consider such unions dangerous to children.

“The fact is that there are no scientifically valid studies tending to establish a negative impact on the adjustment of children raised by an intact same-sex couple as compared with those raised by an intact opposite-sex couple,” Downing wrote.

He concluded that barring same-sex partners from marriage was “not rationally related to any legitimate or compelling state interest.”

Gay marriage opponents were disappointed by the ruling.

“I’m disappointed that we even have to be deliberating a well-precedented matter that people previously defined as a marriage between a man and a woman,” said state Sen. Val Stevens, a Republican who intervened in the case. “What’s to say we can’t call a sister-brother union marriage? Where do you draw the line?”

Massachusetts is the only state to allow full-fledged gay marriage, the result of a historic court decision last year that had a polarizing effect around the country.

Although 38 states have laws defining marriage as a union between a man and a woman, several states have been pushing for constitutional amendments to ban gay marriage out of fear a court could toss aside state laws. Missouri voters soundly passed such an amendment Tuesday, and as many as 12 others could hold similar votes this year.

Jennifer Pizer, lead counsel in the case for Lambda Legal Defense, declined to speculate on the case’s prospects before the state Supreme Court, but noted the justices had sided with gay couples in two earlier cases.

“Judge Downing saw the couples in the courtroom, and he’s recognized that they are full and equal citizens of Washington. No more and no less,” said Pizer.