Pope Francis has strongly criticized modern theories that consider people's gender identities to exist along a spectrum, saying such theories do not "recognize the order of creation."
Speaking of gender theory in an interview in a new book released in Italy, the pope even compares such theories to genetic manipulation and nuclear weapons.
Gender theory is a broad term for an academic school of thought that considers how people learn to identify themselves sexually and how they may become typed into certain roles based on societal expectations.
Asked in the book about how important it is for Christians to recover a sense of safeguarding of creation and sustainable growth, the pope first speaks of the duty of all people to respect and care for the environment.
But he then says that every historical period has "Herods" that "destroy, that plot designs of death, that disfigure the face of man and woman, destroying creation."
"Let's think of the nuclear arms, of the possibility to annihilate in a few instants a very high number of human beings," he continues. "Let's think also of genetic manipulation, of the manipulation of life, or of the gender theory, that does not recognize the order of creation."
"With this attitude, man commits a new sin, that against God the Creator," the pope says. "The true custody of creation does not have anything to do with the ideologies that consider man like an accident, like a problem to eliminate."
"God has placed man and woman and the summit of creation and has entrusted them with the earth," Francis says. "The design of the Creator is written in nature."
Francis makes his remarks in the Italian book Pope Francis: This Economy Kills, which recounts and analyzes the discourses, documents and interventions of the pope on the themes of poverty, immigration, social justice, and safeguarding of creation.
Written by veteran Italian journalists Andrea Tornielli and Giacomo Galeazzi, the book, released last month, concludes with an interview given by Francis to the authors in October.
While the Italian daily La Stampa released the major part of that interview online in January, several portions of the interview are printed only in the book.
Francis' remarks on gender theory in the book follow similar remarks he made in a press conference on the papal plane in January in which he criticized what he called "ideological colonization" of less developed countries by those with more resources.
Recounting the story of a public education minister he knew who was offered money to construct new schools for the poor, Francis said to receive the money, the minister had to agree to use a course book with students that taught gender theory.
"This is the ideological colonization," the pope said. "It colonizes the people with an idea that changes, or wants to change, a mentality or a structure."
"It is not new, this," he continued. "The same was done by the dictators of the last century. They came with their own doctrine -- think of the Balilla [youth groups of Fascist Italy], think of the Hitler Youth."
Francis' reference to creation being inscribed with the designs of God seems to be a reference to the Catholic theological notion of natural law, an idea that nature itself carries a moral message that can be deciphered using the human faculty of reason.
The portion of the interview in the new book that contains Francis' remarks on gender theory also finds the pope touching on what he calls the need for all people, not just Christians, to protect creation.
"Creation is a gift that God has given to man to keep custody over it, to cultivate it, to use if for sustenance and to give it to future generations," the pope says.
"The vocation to guard is human before Christian, it regards all: It is the custody of creation -- its beauty -- it is to have respect for all the creatures of God and for the environment in which we live," Francis continues.
"If we fail in this responsibility, if we do not take care of our brothers and of all creation, destruction advances," he says.
Another portion of the interview that was not released online finds the pope answering a question about his repeated remarks that the global market system "kills."
Speaking of his apostolic exhortation, Evangelii Gaudium ("The Joy of the Gospel"), Francis says in that exhortation that "I did not say anything that was not contained in the teachings of the social doctrine of the Church."
The pope also says he did not speak "from a technical point of view" but "searched to describe what is happening."
"The only specific citation was for the 'trickle down' theories, according to which every economic growth, favored by the free market, succeeds in producing in itself a better social equity and inclusion in the world," the pope states.
"That was the promise that when the glass might have been full, it would be transferred and the poor might have benefited from it," he continues. "It happens instead that when it's filled, the glass magically grows, and like this nothing ever falls out for the poor."
"I repeat, I did not speak technically, but according to the social doctrine of the Church," the pope says. "This does not mean to be Marxist. Maybe the one who has made this comment does not know the social doctrine of the Church and, at bottom, does not even know Marxism well."