VATICAN CITY (RNS) — A new Vatican doctrinal note describes marriage as an exclusive and “indissoluble union” between one man and one woman, reaffirming the Catholic Church’s criticism of polygamy and polyamory.
The document, “One Flesh: In Praise of Monogamy,” was approved by Pope Leo XIV on Friday (Nov. 21) and published on Tuesday, when it was presented by the Vatican head of the doctrinal department, Cardinal Víctor Manuel Fernández, during a press conference at the Vatican.
“Polygamy is in opposition with moral law. It radically contradicts conjugal communion,” the document states in Italian.
Questions surrounding polygamy in Africa were being addressed by one of 10 study groups created after bishops and laypeople gathered at the Vatican in October 2024 for the Synod on Synodality. In their interim reports, the study group on polygamy said it had submitted its findings to the Vatican’s doctrinal department and that it would soon issue a final report offering suggestions and reflections on the matter.
A theme woven throughout the document is that monogamy protects the equality and dignity of women.
“There is no place for some form of polyandry, no polygamy,” the document states, citing St. Thomas Aquinas, who likened having many wives to “a form of slavery.”
Fernández said the document does not wish to “go against polygamy, but to cultivate monogamy.” He said the doctrinal department is in dialogue with local churches in Africa and other parts of the world where polygamy is widespread continues.
The new doctrinal document is also the first time the Vatican has addressed “different public forms of non-monogamous unions — sometimes called ‘polyamory’ — that are growing in the West,” alongside issues such as infidelity and sexualization on social media. About one third of Americans say that open marriages are “somewhat or completely acceptable,” according to a 2023 Pew Research Center study, with the percentage as high as 50% among Americans under 30.
Fernandez has written extensively on the relationship between faith and sexuality. He’s pushed back against sex as a merely procreative impulse, and the new doctrinal document includes traces of his vision. The document states that monogamy is essential to respecting the dignity of every individual, including during sex, citing Pope John Paul II. It separates marital sex from being necessarily tied to “a conscious and desired means of procreation,” adding that sexual “enjoyment” is not incompatible with the dignity of marriage. It also upheld the importance and validity of marriages without any children.
Two paragraphs in the document reaffirmed the teachings in Pope Paul VI’s 1968 document “Humanae Vitae,” on responsible parenthood and natural family planning, while rejecting artificial contraception.
The new doctrinal note was released on the United Nations’ International Day for the Elimination of Violence Against Women and includes extensive reflections on violence against women and stresses that “marriage is not ownership.”
Fernández said people should seek to fill the emptiness in their hearts through other means rather than subjugating others to their will.
“What we say (in this document) can also be valuable for other types of union,” Fernández said, adding that those who are celibate and LGBTQ individuals can also find useful guidance for their relationships. The document itself makes no explicit mention of homosexuality.
In a society dominated by technology and sexualization on social media, the document offers to provide an education for young people on the importance of relationships and marriage not as something archaic, but as anticipation of the “mystery of God himself,” it reads.