The court ruled in an 8-2 vote that the Mexican capital's legalization of gay marriage in December does not violate the national constitution. On Monday, it is expected to take up the constitutionality of adoption by gay couples and whether same-sex marriages would have federal protection nationwide.

"We have nothing to celebrate until the court finalizes the issue of adoptions," said Enoe Uranga, an openly gay federal legislator who was key in getting the Mexico City law passed. "It's not finished as long as they don't declare that gay couples have all the rights of anyone else."

Armando Martinez, president of the Association of Catholic Lawyers, which supported the challenge to Mexico City's law brought by Mexico's attorney general's office, said preventing gay adoption was the most important issue.

"The judges unfortunately refused to listen to the citizens' will," he said.

Issue stirs passions

Gay marriage is at least as controversial in overwhelmingly Roman Catholic and socially conservative Mexico as it is in the United States. The Catholic hierarchy has staunchly argued that marriage is reserved for a union between a man and a woman.

Mexico City's legislative assembly, dominated by the left-of-center Democratic Rev- olution Party, approved gay marriage a few days before Christmas last year.

The law deepened an earlier legalization of civil unions, but stopped short of approving gay adoptions.

320 couples wed

The law took effect in March and as of this week, 320 same-sex couples have been wed in the Mexican capital. Coahuila state, which borders Central Texas, has legalized same-sex civil unions, which provide much the same legal guarantees as marriage.

Supreme Court justices who upheld Mexico City's law Thursday varied in their reasoning, with some arguing in favor of individual rights and others in states' rights to set their own laws.

Jalisco and Baja California, two states governed by President Felipe Calderon's conservative National Action Party, also have challenged the gay marriage law before the Supreme Court, arguing it will negatively affect them.

On heels of U.S. ruling

Thursday's ruling by the Mexican jurists came a day after a U.S. federal judge struck down as unconstitutional voters' reversal of legalized gay marriage in California. That ruling has been appealed and likely will be decided by the U.S. Supreme Court.

Argentina legalized gay marriage last month over strenuous opposition from the Catholic Church, the first Latin American country to do so. It joined Canada, Spain, South Africa, Sweden, Norway, the Netherlands and Belgium in recognizing gay marriage rights.

dudley.althaus@chron.com