Same-sex couples made history in Mexico City this month by marrying under the first law in Latin America that explicitly approves gay marriage. The law allows only residents of the capital to tie the knot, although marriages will be recognised in other states. Mass weddings are expected later this month. The law, passed on 22 December  and put into effect on 4 March, will also allow same-sex couples to adopt children.

“What we were looking for is the same rights. We do not want special rights or any special law to protect or recognise our relationship,” Gloria Careaga, the co-secretary general of the Mexico branch of the International Lesbian, Gay, Bisexual and Transsexual Association (ILGA), said. “This law brings an opportunity to build on a new perspective about the social structure and the social framework that we are living in today.”

Mexico City's leftist government introduced the law, with Marcel Ebrard, Mexico City's mayor, attending some of the first marriages. The city's legislators are pushing forward with reforms to social legislation, having already passed a law permitting abortion in the first twelve weeks of pregnancy.

The opposition Party of the Democratic Revolution (PRD) is backing the move as a rights issue, linked to that of abortion and adoption, which it says cannot be left to the judgment of public opinion. “We feel that sexual preferences should not interfere with human rights. And that gay marriage is part of those human rights,” Saul Escobar, the PRD’s secretary for international relations, said. “Maybe there are going to be very few [homosexual couples] who are going to adopt. But still, to have the right is important and the people are slowly going to accept that that has to do with tolerance, and freedom, and liberty.”

But the law still faces opposition in the traditionally conservative Roman Catholic nation. The federal government lodged a constitutional appeal against it concerning “protection of the family” at the Supreme Court last month.

“It is the obligation of the state and the law to protect the characteristics of relationships between a man and a women… We respect relationships between men and men or women and women profoundly. [But] they are very different from the relationship between men and women, and require very distinct legislation,” Fernando Rodriguez Doval, a district assembly member for the National Action Party (PAN) of Filipe Calderon, the president, and the federal government, said.  “We do not look at the right of the couple to have a child, but the right of the child to have a proper family."

Rodriguez said that the PRD was trying to gain political support by backing the law.

For the Roman Catholic church, influential particularly outside the capital, the institution of marriage is at stake.“The Church considers a marriage to be a union between a man and a woman which opens the way for procreation,” Father Jose de Jesus, of the archdiocese of Mexico, said. “The Church says that there is a difference. We give a totally different name to marriage between a man and a woman and the bond between two men or two women.” Allowing homosexual couples to adopt would create a family model that “children would not wish to have”, as well as being socially problematic for them, he said, adding that even if homosexuals have the legal basis for rights, in practice homophobic groups could still restrict them.

Some polls state that more than 70 per cent of Mexico City residents support homosexual marriage, while only about 40 per cent back adoption by gay couples.

Rodriguez maintains that the new law was not necessary, since Mexico City’s assembly already passed a civil union law in 2007, “So the debate should be to perfect this [original] law.”

However, gay rights activists say that the earlier legislation only recognized relationships between two homosexuals, not allowing them to adopt children, secure loans, benefit from partners’ insurance policies and inherit without paying tax.

The movement to allow homosexuals to marry came out of the necessity for legal security and recognition borne from the rise of Aids in the 1980s and homosexuals with children leaving their heterosexual unions.

As Careaga argues, the idealized vision of a nuclear family is no longer universal in Mexico, with about a third of families being designated non-traditional, for instance having single parents or a same-sex couple. Some legal advisors think an appeal ruling could take a year or more, but activists expect the law to remain and help spread rights. “There are many voices now that I really didn’t think would speak up in defence of this position,” Careaga said, adding:

“The opportunity that this law brings to [homosexual] people from all over the country is that they can come to Mexico City and get married here and go back to their own state and try to look for the recognition of this marriage. And I think that this is the next step after the court declaration that we are going to start working on.”

For now same-sex couples in Mexico City are making the most of their new-found rights, continuing the trail blazed through Latin America, first by Argentina, which had its first homosexual wedding last December, and then Uruguay, which approved gay adoption last September. But in the face of Catholic conservative forces, the progress made by the city legislature remains tenuous.