ROME — The Vatican on Tuesday doubled down on the value of monogamous marriage between a man and woman, responding to concerns raised by African bishops about the practice of polygamy in their flocks.

The document from the Vatican’s doctrine office said the Catholic Church had a well-documented position upholding the indissolubility of marriage as a lifelong union between spouses. But it said the church’s position on the unique and exclusive nature of a monogamous marriage was less well known.

In recent years at Vatican meetings of bishops, African delegates have regularly complained that polygamy is widely practiced among their flocks and asked the Vatican for guidance.

“A Dear One: In Praise of Monogamy” provides them with a doctrinal document tracing the way marriage has been treated in the Bible, poetry, Christian theology and philosophy and by various popes and church councils across history.

The document is 40 pages long with 256 footnotes and written only in Italian. In the introduction, the Vatican’s doctrine chief and author, Argentine Cardinal Víctor Manuel Fernández, says it’s enough to read the final chapter, on “conjugal charity” and the conclusion, to take away its essential message.

Catholic doctrine holds that the sacrament of marriage is a lifelong, exclusive union between man and woman, open to new life.

The final section of the new document deals with sexuality, procreation and sexual attraction between couples and recalls Fernández’s previous writings on the topic.

When the Argentine theologian was appointed by Pope Francis in 2023, he came under fire from conservatives who had unearthed an out-of-print book of his, “Heal Me with Your Mouth. The Art of Kissing.” A year later, another out-of-print Fernández title and similar in tone, “The Mystical Passion: Spirituality and Sensuality,” caused a stir.

The short expose about mystical-sensual experiences with God delved into orgasms, including graphic descriptions of male and female sexual anatomy and his commentary about sexual desire, pornography, sexual satisfaction and domination, and the role of pleasure in God’s mystical plan.

Neither title was included in the list of publications the Vatican provided when Francis named Fernández as prefect of the Vatican’s Dicastery for the Doctrine of the Faith and gave him marching orders to radically change the office’s course.

Fernández was the author of one of the most controversial documents of Francis’s pontificate, the 2023 doctrinal statement allowing Catholic priests to bless same-sex couples. The statement prompted an unprecedented rebuke by African bishops, who in a unified statement refused to follow it.