Pope Benedict XVI
An Italian priest set a photo of Benedict XVI on fire during Sunday Mass, arguing that the former pope had abandoned followers of the Roman Catholic Church by resigning. Reuters

Pope Benedict XVI said in his World Day Of Peace 2013 address last week that gay marriage is a threat to “justice and peace” in the world. The 85-year-old religious leader even said that same-sex marriage is "unnatural” as any support of same-sex union offends the natural laws of faith and justice.

The Associated Press reported that the head of the Roman Catholic Church announced the beginning of the Christmas season Friday with the traditional lighting of the tree in St. Peter's Square in the Vatican City. The Holy See also released the Pope’s special message for World Day of Peace 2013 on the same day.

According to a report by Gay Star News, the Pope suggested in his annual address that same-sex marriage is “unnatural” and "against human nature.” Here is an excerpt from the speech of the religious leader:

There is also a need to acknowledge and promote the natural structure of marriage as the union of a man and a woman in the face of attempts to make it juridically equivalent to radically different types of union; such attempts actually harm and help to destabilize marriage, obscuring its specific nature and its indispensable role in society.

These principles are not truths of faith, nor are they simply a corollary of the right to religious freedom. They are inscribed in human nature itself, accessible to reason and thus common to all humanity. The Church’s efforts to promote them are not therefore confessional in character, but addressed to all people, whatever their religious affiliation. Efforts of this kind are all the more necessary the more these principles are denied or misunderstood, since this constitutes an offence against the truth of the human person, with serious harm to justice and peace.

This was not the first time when Pope Benedict XVI has opposed gay marriage. His stance on same-sex marriage has largely been constant. Earlier, in September, the Pope said that gay people are not fully developed humans as they disobey Catholic law.

He was also quoted in the past saying that same-sex marriages are "insidious and dangerous" and a "threat to humanity."

The Catholic Church, which has more than 1.2 billion followers worldwide, teaches that homosexual acts are against the Church. Officials around the world have also protested against moves to legalize gay marriage across Europe and other developing countries worldwide.

During his time as Prefect of the Congregation for the Doctrine of the Faith (CDF), Benedict XVI took several efforts to tackle the issue of homosexuality within the Church and the wider world. In 1986, the CDF sent a letter to all bishops entitled “On the Pastoral Care of Homosexual Persons,” in which it was clarified that the Church's position on homosexuality was that "although the particular inclination of the homosexual person is not a sin, it is a more or less strong tendency ordered toward an intrinsic moral evil; and thus the inclination itself must be seen as an objective disorder.”

In 2008, the Pope delivered an end of year message to the Roman Curia in which he said that the distinction between men and women is central to human nature. He also said that “this order, set down by creation, be respected." According to him, gender roles that deviate from his view of what gender roles should be are "a violation of the natural order."

Predictably, the pontiff's views on same-sex union have irked the Lesbian, Gay, Bisexual and Transgender (LGBT) groups such as the Italian Arcigay and the German Lesbian and Gay Federation (LSVD). They dubbed the Pope's comments on homosexuality as homophobic. "A divine program for men and women is out of line with nature, where the roles are not so clear,”Aurelio Mancuso, head of Arcigay said.

Meanwhile, Pope Benedict XVI’s recent comment on gay marriage has angered activists, leading to a small protest in St. Peter’s Square during the pontiff’s weekly address, the AP has reported.

The protesters carried signs in different languages, saying: ‘‘Marriage for All’’ and ‘‘Homophobia (equals) death.’’ The organizers of the protest also issued a statement saying: ‘‘Gay unions don’t harm peace. Weapons do.’’