*Updated with official statement from Paloma Ovejero, vice director of the Holy See press office

A congratulatory letter sent from Pope Francis to a same-sex couple regarding the baptism of their children was a standard form letter sent to all who write to the Pope, a Vatican source has confirmed.

The letter was not an endorsement of gay unions, the source told CNA, and the Pope may not have known that the letter was going to a gay couple, since it was addressed to a single individual.

Tony Reis, an LGBT activist, and his partner David Harrad published on Facebook in April that they sent a letter to the Pope, telling him about the baptism of their three adopted children in a church in Curitiba, Brazil.

The couple told AFP that they had received a congratulatory letter in return, signed by the Vatican Secretariat of State, Monsignor Paolo Borgi.

The letter, translated from Portuguese, said that the Holy Father "looks with appreciation" at the letter on the baptism of the children, and "expressed his feelings of esteem...and his wishes for the good spiritual fruits of his ministry as Pastor of the Universal Church."

"Pope Francis wishes him well, invoking for his family the abundance of divine graces, so that they may live constantly and faithfully the condition of Christians, as good children of God and of the Church, and sends them a propitious Apostolic Blessing, asking them not to stop praying for him," the letter concludes.

Along with the letter in Portuguese, the couple received a photograph of the Pontiff.

"(T)hat letter is the standard model of courtesy response that the Vatican sends to all the people who write to the Pope, and therefore was not a letter (that was) expressly thinking about them," the Vatican source told CNA.

The same source said the letter is addressed to one person, "further evidence that the Secretary of State was unaware that it was a homosexual couple" who had written the first letter. The couple has not published the text of the letter they sent to Pope Francis, so it is unknown whether they presented themselves as a same-sex couple.

In an official statement to CNA, vice director of the Holy See press office Paloma Ovejero confirmed that the perception that this letter was an affirmation of same-sex marriage "is false. The letter was directed only to him (Reis)." The Vatican letter is only addressed to one person with the greeting "Dear Sir."

"Although it is true that in the body of the response there was a reference to a blessing of the family of the recipient, in Portuguese this expression has a generic and ample meaning, equivalent to 'all the people close to you,'" Ovejero told CNA.

She added that in the text of the Vatican letter "there is no element whatsoever that makes reference to the concrete content of Mr. Reis' letter, except for the gratitude of the Pope for the expression of 'esteem and veneration to the Pastor of the Universal Church.'"

In 2015, the Vatican clarified a similar incident, when Fr. Ciro Benedittini, the deputy director of the Vatican Press Office, confirmed that a standard form letter sent to a lesbian couple who had written the Pope was not an endorsement of same-sex marriage.

On numerous occasions throughout his papacy, Pope Francis has reaffirmed Church teaching on marriage, voicing concern about what he sees as attacks on marriage and the family.

"(T)he family – as God wants it, composed of a man and a woman for the good of the spouses and also the generation and education of children – is deformed by powerful contrary projects supported by ideological colonization," the Pope told a group in Rome in September 2015.

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That same year, he voiced support for "efforts in defense of the family" in a greeting to pilgrims from Slovakia, on the day before a country-wide vote on whether to legalize same-sex unions.

Speaking during a trip to the Philippines, Pope Francis warned bluntly, "The family is also threatened by growing efforts on the part of some to redefine the very institution of marriage."

And in an October 2014 audience, he warned that "the family is being bastardized," cautioning against a common view in society that "you can call everything family, right?"

"What is being proposed is not marriage, it's an association. But it's not marriage! It's necessary to say these things very clearly and we have to say it!" he stressed, lamenting that there are so many "new forms" of unions which are "totally destructive and limiting the greatness of the love of marriage."