Say “family issues” to most Americans or Europeans, and they’re likely to flash on divorce, or the challenges of single-parent households, or perhaps same-sex relationships and the push for gay marriage.

What probably wouldn’t come naturally to mind is polygamy. Yet in many parts of the non-Western world, polygamy is a major feature of family life, and thus a major pastoral challenge for the Catholic Church.

Discussion of polygamy is likely to surface at the Oct. 5-19 Synod of Bishops on the family in the Vatican, and could be a factor in the politics of an expected debate over whether the church’s ban on divorced and remarried Catholics receiving communion ought to be revised.

Polygamous marriage (also referred to as “polygyny”) is widely practiced in many regions of the world, including Africa, the Middle East, and parts of Asia.

Though estimates vary, sociologists believe that tens of millions of men and women worldwide are involved in some form of polygamous marriages. In Senegal, for instance, nearly 47 percent of marriages involve multiple partners, according to United Nations figures.

Facing those realities, some churches in Africa have tried to encompass polygamy within the traditional Christian understanding of marriage.

In 1987, the Fifth General Assembly of the All-Africa Conference of Churches, a Protestant ecumenical body, concluded that “the rather harsh attitude of the Church has been a painful but real cause of disintegration of some otherwise stable marriages and families.” In 1988, the Lambeth Conference of the Anglican Communion decided to admit polygamists under certain circumstances, in response to pressure from bishops in Kenya and Uganda.

Catholicism, however, has held the line. Speaking to a Black Catholic Congress in the United States in July 2007, Cardinal John Onaiyekan of Abuja, Nigeria, said that on polygamy, “the Catholic Church is particularly firm and consistent, giving no room whatsoever for doubts and exceptions.”

The church’s tough stance has been shaped not only by defense of tradition, but also impressions that polygamy discriminates against women. In the late 1990s, a survey of African Catholic theology cited 23 female African Catholic theologians who argued that since mutuality and equality are Biblical ideals, Scripture should not be used to justify polygamous marriage.

On the other hand, some Catholic bishops and theologians support greater pastoral flexibility in dealing with the complicated realities of polygamy. Cardinal Peter Turkson of Ghana made this argument at a 2005 Synod of Bishops in the Vatican.

“You can’t just say to a man, let the other [wives] go and stay with the first wife,” Turkson said. “There’s a question of justice. You can ask the man to provide for her ongoing security, setting up a small business for her, for example.”

“There’s also [the wives’] need for a sexual partner,” Turkson said. “You can’t just say to everyone they should be celibate. … You don’t want to expose them to prostitution and so on.”

When cardinals from around the world met in Rome last February to set the table for the October synod on the family, some prelates from non-Western cultures hinted that polygamy may drive them to oppose any change in the ban on divorced and remarried Catholics receiving the sacraments.

Their argument went like this: The Catholic Church has been telling people in polygamous marriages that they have to change because marriage means one man and one woman, for life. If the Church softens that teaching for the divorced and remarried, it might face pressure to cut a deal for polygamists, too.

“You had cardinals from the Third World who got up and said that if they’re dealing with polygamy issues, they don’t want to hear about divorce,” said Cardinal Daniel DiNardo of Houston, Texas.

DiNardo paraphrased their message as, “If you try something with this, it’s going to hurt us on polygamy.”

“They’ve been telling people that if you come into the church, you’ve got to choose one wife,” DiNardo said. “If you suddenly change that, couldn’t [people in polygamous marriages] say, ‘Why can’t you give me a break, too?’ ”

Cardinal Vincent Nichols of Westminster in the United Kingdom said at the time it was important to hear these voices.

“To think of the church purely from the point of view of Europe, and our preoccupations in Europe, is not to see the whole picture,” he said.

Not all African prelates, however, see polygamy as an impediment to rethinking the communion ban.

“I don’t think giving consideration to the divorced and remarried would create any problem for the ministry of marriage in Africa,” said Turkson in a March 2014 Boston Globe interview.

Instead, Turkson said that what he’d like to see from the Synod of Bishops is a broadening of the church’s discussion beyond the Western model of a two-parent nuclear family, to bring into view Africa’s experience of broader ties within a clan.

“For us, ‘family’ often means extended relationships within the clan, composed of several smaller family units together that give support to one another and provide rules for family life,” he said.

An exclusive focus on Western problems such as divorce and cohabitation, Turkson argued, risks leaving Africa out of the picture.

Whatever impact polygamy has on the divorce debate, it seems clear it will be in the air when the bishops talk family issues this October.

If that strikes some Catholics in Europe and North America as odd, consider it a lesson in the realities of a global church. Two-thirds of the 1.2 billion Catholics in the world now live outside the West, and increasingly their priorities and concerns are destined to set the global agenda.

In other words, Westerners probably ought to get used to seeing polygamy on the church’s working list of “family issues.”