A ruling on whether California's gay marriage ban is unconstitutional is expected Wednesday, the AP reported.

Chief U.S. District Judge Vaughn Walker will hand down his verdict on Proposition 8 in the afternoon, court spokeswoman Lynn Fuller said.

The measure's November 2008 approval struck a severe blow to the gay marriage movement, denying gay and lesbian couples in the country's most populous state the right to marry just months after the state's highest court had legalized the institution.

About 18,000 gay and lesbian couples married before voters narrowly reversed the ruling.

Walker heard 13-day's worth of testimony in January and final arguments in June.

“We conclude this trial, your honor where we began,” Ted Olson, who is representing two gay couples, said during closing arguments. “This case is about marriage and equality. The fundamental constitutional right to marry has been taken away from the plaintiffs and tens of thousands of similarly situated Californians.”

Olson and his team argued that proponents of Proposition 8 had approved the measure out of animus towards gay men and lesbians, stripping such couples of their constitutional rights.

But Charles Cooper, who represents Protect Marriage, the primary sponsor of Proposition 8, strongly disagreed.

“Religions that condemn homosexual conduct also teach love of gays and lesbians,” he said.

In his closing arguments, Cooper said marriage was designed to discourage “irresponsible procreation,” which does not apply to gay couples. Gay and lesbian couples, he said, would only participate in responsible procreation because they would require a third party.

Lawyers arguing in favor of the ban have also asked Walker to revoke state recognition of the 18,000 marriages performed during the five month window when gay marriage was legal. In a brief filed Tuesday, they asked Walker to stay his decision if he overturns the ban.

“Same-sex marriages would be licensed under a cloud of uncertainty, and should proponents succeed on appeal, any such marriages would be invalid,” they wrote.

Both sides have already said they'll appeal if Walker does not rule in their favor.

Gay rights advocates have previously avoided federal courts because of the possibility that the case would reach the Supreme Court, which they said remains too conservative.

But today's ruling is likely headed in that direction.