A federal court judge has ruled that the United States constitution does not stop the state of Louisiana from defining marriage as the union of one man and one woman.
Judge Martin Feldman found against two same-sex couples who were attempting to have their marriages recognised in the state.
He has become the third federal judge to rule that traditional marriage laws are constitutional.
In his decision, Judge Feldman said that the state of Louisiana has a legitimate interest in “linking children to an intact family formed by their two biological parents”.
Referring to same-sex marriage, he said: “This Court is powerless to be indifferent to the unknown and possibly imprudent consequences of such a decision.”
His comments were welcomed by the National Organization for Marriage (NOM), which campaigns for traditional marriage.
Brian Brown, the president of NOM, said: “This is a great win for the cause of marriage, coming as it does on the heels of other pro-marriage court victories”.
He continued: “Judge Feldman has authored a powerful opinion that points the US Supreme Court in the direction of upholding state marriage laws and constitutional amendments.”
Proponent of same-sex marriage have argued that a redefinition of marriage in the Supreme Court is inevitable. However, Mr Brown described this claim as a “myth”.
He said: “Overwhelmingly, voters have rejected redefining marriage, and we expect the US Supreme Court to do so as well.”
At the end of August, the US Supreme Court unanimously ruled to delay same-sex marriages taking place in Virginia.
A lower court in the state had overturned a voter-approved amendment that defined marriage as between a man and a woman. However, a county clerk asked for the ruling to be delayed and his request was granted.
Last year, the Supreme Court ruled that each state could decide for itself whether it wants same-sex marriage.
Local courts in Florida, Mississippi and Tennessee have also upheld traditional marriage laws.