A friend recently told me that the Vatican released a document last year about the Church’s teaching on monogamous marriage. Can you tell me something about it?
The document, Una Caro: In Praise of Monogamy, was issued by the Dicastery for the Doctrine of the Faith on 25 November 2025 and was approved by Pope Leo XIV.
Una Caro, which is Latin for “one flesh”, aims to offer a theological, pastoral, and cultural reflection on marriage as a monogamous union between one man and one woman. It was released in view of growing debates around the world about marriage, polygamy, and various other non-monogamous relationship models.
The document serves as a theological and pastoral resource for bishops, pastors, and lay faithful, particularly in contexts where cultural and social pressures challenge the Church’s constant teaching on monogamy. We should be aware that it is not only the Catholic Church that teaches that marriage is the union of one man and one woman. Australia’s Marriage Act 1961 defined marriage as “the union of a man and a woman to the exclusion of all others, voluntarily entered into for life”.
At the heart of Una Caro is the assertion that marriage is an “indissoluble unity”, a bond that is both exclusive and reciprocal. This unity reflects what Scripture calls “one flesh,” a phrase that expresses the mutual belonging and total self-giving of the spouses to each other. The document emphasises that this union is not a restriction on freedom but rather is its fullest expression: freedom shared in love and offered entirely to one another.
The text argues that monogamy should not be seen as a cultural remnant or a moral burden, but as a profound expression of human dignity and vocation. In an age shaped by individualism and consumerist attitudes like the “throw away” culture that often reduce human relationships to matters of mere convenience or desire, the document reaffirms a vision of love that is total, committed, exclusive, and oriented toward the good of the other.
A key emphasis throughout the document is that this exclusive belonging does not equate to possession but is rather grounded in mutual respect, love and freedom. Spouses belong to one another in a way that honours each other’s dignity and identity, and this belonging is not ownership, but a freely chosen self-giving.
Una Caro is based on Scripture, the tradition of the Church Fathers, theological reflection, and the Church’s magisterium. The document traces how the Fathers, medieval and modern writers, theologians and Popes have emphasised the unitary and exclusive nature of marriage across the centuries. Genesis 2:24 establishes the original intention of God for marriage as a union of one man and one woman becoming “one flesh.” Jesus reiterates this, reaffirming monogamy as God’s design from the beginning of creation (cf. Mt 19:3-12). And Saint Paul’s letter to the Ephesians further presents the marital union as a sign of the union between Christ and the Church (cf. Eph 5:31-33).
One of the motivating concerns behind Una Caro is the way modern cultures, both in the West and in parts of Africa and other continents, are grappling with different models of human relationships. As regards polygamy, the document responds to pastoral inquiries from bishops in regions where polygamy remains culturally entrenched. While acknowledging that historical practices of polygamy appear in the Old Testament, Una Caro stresses that the Christian understanding of marriage calls for an exclusive, lifelong union between one man and one woman.
In the West, the rise of polyamory and other consensual non-monogamous relationships has prompted pastoral reflection on the meaning of commitment and fidelity, emphasising that human love finds its fullest expression in singular, committed mutual self-giving. Moreover, the unity of the spouses is a promise of the infinite, pointing beyond human limitations toward God’s fidelity.
By affirming the dignity and equality of the spouses, the document invites the Church and the world to consider monogamy not as a mere institution but as a theological and existential gift, one that reflects God’s faithful love and enriches human flourishing.
