Australian law permitting only opposite-sex marriage does not amount to gender discrimination, a federal court judge in Sydney has ruled.

Justice Jayne Jagot said that neither gay men nor women are allowed to marry under the Sex Discrimination Act of 1984 and thus both sexes are treated equally to that extent.

“A man cannot enter into the state of marriage as defined with another man just as a woman cannot enter into the state of marriage with another woman,” the judge wrote. “The redress for these circumstances lies in the political and not the legal arena.”

The case, Margan v President, Australian Human Rights Commission, was decided last Thursday.

The Australian parliament rejected a private member’s bill which proposed to permit same-sex marriage in September.

Prime Minister Julia Gillard joined the opposition parties in defeating the legislation by 98 votes to 42.

The ruling upheld the Australian Human Rights Commission’s decision to reject a complaint from Simon Margan, an activist who had sought an order directing the states of New South Wales and Queensland to register same-sex marriages.

Sex discrimination depends on a comparison between the treatment of the person of one sex with the treatment of the opposite sex, Jagot wrote in her ruling.

“There cannot be discrimination by reason of the sex of a person because in all cases the treatment of the person of the opposite sex is the same,” she wrote.

In Australia, the Marriage Act defines marriage as the union of man and a woman to the exclusion of all others, Jagot wrote.

“By statutory definition, persons of the opposite sex may marry and persons of the same sex may not,” the judge said.