A national gay rights organization is joining a lawsuit to overturn the state's constitutional ban on same-sex marriage.

The Associated Press reported Wednesday morning that Lambda Legal announced its participation in the suit that is being appealed to the 5th U.S. Circuit Court of Appeals in New Orleans.

A U.S. district judge in New Orleans upheld the state's ban in September, AP reported.

Lambda Legal describes itself as the nation's oldest and largest legal organization seeking full recognition of the civil rights of lesbians, gay men, transgender people, and people with HIV.

Other appeals courts around the nation have been striking down gay marriage bans in various states. The 5th Circuit case could become significant in light of this week's U.S. Supreme Court refusal to take up those other appeals.

A state district judge in Lafayette called the state's same-sex marriage ban unconstitutional during an adoption case involving two gay women.

The Associated Press contributed to this report.