Lawyers in San Francisco along with Californian gay groups have this week asked the state Supreme Court to decide whether barring same-sex couples from marriage violates the California Constitution.

It comes after Colorado, Idaho, South Carolina, Tennessee, South Dakota and Virginia all passed gay marriage bans in a ballot earlier this month.

The couples, Equality California, and Our Family Coalition are represented by lead counsel from the National Centre for Lesbian Rights (NCLR), Lambda Legal, the American Civil Liberties Union (ACLU), Heller Ehrman LLP, and the Law Office of David Codell.

This case is being considered together with the other marriage cases under the title In re Marriage Cases.

In April 2005, San Francisco Superior Court Judge Richard A Kramer ruled that barring same-sex couples from marriage unconstitutionally discriminates on the basis of sex and violates the fundamental right to marry.

The California Court of Appeal overturned Judge Kramer’s ruling in a 2-1 decision last month, saying that California may continue to bar same-sex couples from marriage. The petition filed today asks the California Supreme Court to reverse the Court of Appeal decision.

More than 250 religious and civil rights organisations, including the California NAACP, Mexican American Legal Defence and Educational Fund, California Council of Churches, Asian Pacific American Legal Centre, and National Black Justice Coalition, filed amicus briefs supporting marriage equality for same-sex couples.

In 2005, the California Legislature passed AB 849, the Religious Freedom and Civil Marriage Protection Act sponsored by Equality California, which would have ensured equal treatment under the law by allowing same-sex couples to marry in California. Governor Schwarzenegger vetoed the bill.

The California Supreme Court has 60 days to rule on the petition, and may extend that period by not more than an additional 30 days.