Brazil's high court will hear a legal challenge to the country's prohibition on civil unions for gay and lesbian couples.

Justices will begin hearing arguments on Thursday after opening deliberations on Wednesday, the AFP reported.

The challenge was filed by Rio state Governor Sergio Cabral. Cabral's state recognizes gay couples with civil unions.

An effort to make Brazil the second Latin American country behind Argentina to legalize gay marriage was introduced in March by Representative Jean Wyllys. Gay marriage is also legal in the self-governing city-state of Mexico City, and the nation's highest court has ruled that all states must recognize such marriages. Uruguay lawmakers are also considering a gay marriage bill.

“Until there is a law regulating homosexual civil union and marriage, the high court's recognition of a stable union is the best thing that could happen so that gay couples rights are accepted once and for all,” said judge Maria Berenice Dias.

The lawsuit is supported by President Dilma Rousseff's top prosecutor, Attorney General Roberto Gurgel.

“When the state refuses to recognize a homosexual (civil) union, it is sacrificing rights that parties to that union have,” Gurgel said.