In 2007, Bergoglio publicly criticized Buenos Aires' government for allowing civil unions, Russo said. His relationship with the mayor of Buenos Aires soured over the matter.
Gay rights advocates in Argentina later argued that civil unions, allowed in a several states, were a positive step that conferred some benefits to same-sex couples, but didn't go far enough. The same-sex marriage measure, they said, would treat homosexual and heterosexual relationships equally before the law. It would permit gay couples to adopt, and also allow the inheritance of property.
Argentina approved a law legalizing same-sex marriage nationwide in July 2010.
Even though Bergoglio was one of the law's most well known opponents, Marquez said on Wednesday that he hopes the pontiff will remain open to discussion, just as he appeared to be several years ago in Buenos Aires.
"We are going to try to have a dialogue with the pope," said Marquez, who works for Argentina's National Institute Against Discrimination. "It's frightening, but I think it must be done."
'He's really moderate on this issue'
Word of the pope's reported support for civil unions in Argentina sparked debate, with some praising his stance and saying it was a hopeful sign of possible reforms.
"He wanted to respect human rights. That's the real surprise here, that people say, well he's anti-gay. You can be anti-gay marriage and not be anti-gay, and I think there's a distinction here," said the Rev. Edward Beck, a CNN contributor and host of "The Sunday Mass" on ABC Family. "He's really moderate on this issue, it seems."
Others, though, were more skeptical.
One Argentine journalist said Wednesday that he wasn't quite ready to celebrate.
In an article titled, "Francis, the pope that declares war on us and later calls us on the phone," journalist Bruno Bimbi said it wasn't clear how the pope will handle the issue of same-sex unions.
"Maybe the lion has become a lamb. Maybe, as a priest told me the day his election was announced, maybe he is worried about his biography and wants to go down in history. I do not know," Bimbi wrote. "Whatever he does, this time he won't be able to blame others for the pressures. Now he's in charge."