The Impact of Interfaith Marriage on Catholic Families

Approximately a quarter of Catholics are married to non-Catholics, even among those married in a Catholic parish. As detailed below, interfaith marriages are more likely to have marital problems and produce children who are less religious. Like anything that involves marriage, this can be a very sensitive topic. Those married to a non-Catholic may view even a discussion of this topic or the data as an assault on them or a criticism of their marriage. 

Parents whose children married outside the Faith may see this as a criticism of how they raised their children. Others may push back on the evidence because they know a great and holy woman who is raising her kids Catholic despite her husband’s non-Catholic religious affiliation or lack of faith. They might point to the example of St. Monica and express hope for the conversion of not only the child but the spouse too. Regardless of our personal situation or personal feelings, the data, surveys, and research indicate that marriages to non-Catholics are not good for the faith of the Catholics or their children. St. Monica is so remarkable because that outcome is hard and it took such great faith and perseverance.

For decades there has been a steady supply of research and publications demonstrating the challenges of interfaith marriages. These studies reflect lower happiness in marriage and less marital intimacy. Divorce rates are higher when one spouse attends religious services more frequently than the other. For example, research in the Netherlands reports that marriages between Protestants and Catholics have higher divorce rates than between two Protestants or two Catholics. The same was found in Northern Ireland. Interfaith married people tend to be less religious themselves. The Pew Research Center’s conclusions on interfaith marriages are quite simple:

Adults in religiously mixed marriages are, by and large, less religious than their counterparts who are married to spouses who share their faith. They attend religious services less often, pray less frequently, tend to be less likely to believe in God with absolute certainty and are less inclined to say religion is very important in their lives.

In the Pew survey, 70 percent of self-identified Catholics married to another Catholic scored as “highly” religious. If a Catholic were married to a spouse from another religion, this dropped to 56 percent. If their spouse had no religion, only 46 percent of Catholics scored as highly religious. This is a pretty significant drop on its own, on a scoring system that seems to have some grade inflation built in. The biggest impact may be on the children of such marriages.

One of the most interesting studies on parents transmitting religion to their children was done by Professor Vern Bengtson, who performed 35 years of longitudinal surveys that included in-depth interviews with over 2,000 respondents across more than 350 three-generation families. Instead of just asking a parent or their child about religion in a survey, Bengtson was able to interview the whole family—and to do it over an extended period of time—to track the transmission of faith or failure to do so. 

For same-faith marriages, Bengtson found 68 percent of adult children share their parents’ religion. “For interfaith parental marriages, by contrast, only 38% have adult children who share either the father’s (40%) or the mother’s (36%) religious tradition.” Not only is this a significant drop for either parent’s success in transmitting their religion, but we see that the children of the interfaith marriage can end up with no or neither religion. 

The numbers are even worse for Catholics. In Bengtson’s study, 47 percent of Catholic parents married to Catholics raised children who grew up to be Catholic young adults while only 21 percent of Catholics in interfaith marriages could say the same thing. The interfaith marriage cut the rate of religious transmission for Catholics by more than half.

Perhaps nobody has written more on the topic of religious transmission than Professor Christian Smith of Notre Dame. His research has included multiple iterations of the National Study of Youth and Religion, which included interviews with thousands of teens and follow-ups as they aged. Simply put, young Catholic adults are more likely to attend Mass if both their parents were Catholic. In Smith’s cohort, 16 percent of Catholic young adults ages 18-23 attend Mass weekly. 

This number may be disappointingly low, but only 4 percent of Catholics that age attend Mass weekly if one of their parents is not Catholic but has a religion (presumably Protestantism). If the second parent has no religion, the rate of Mass attendance drops to 2 percent or less. Again, all of these numbers are disappointing and sad, but the significance cannot be ignored. Having two Catholic parents in the household increases the likelihood of weekly Mass attendance four-fold over a Protestant or other parent and eight-fold over a non-religious parent during this critical time in a young person’s life. 

Smith found that marriage outside the Church resulted in the children being half as likely to receive Confirmation. Only 25 percent of those raised in a household with one parent of no religious affiliation had received Confirmation compared to 47 percent of those from a home with two Catholic parents. Once again, both numbers are sad, but the impact of the intermarriage is strong. The rate of receiving first Communion also dropped, falling from 89 percent to 63 percent if the other parent had no religious affiliation. The majority of young adults who were raised by two Catholic parents are Christians; the majority of those raised by a Catholic and a “none” (religiously unaffiliated) are not Christians. Marrying outside the Faith is simply more likely to produce children who are outside the Faith. 

This should not be surprising. When a Catholic enters into an interfaith marriage, it is driven by love for the spouse rather than any consideration of data. But the data shows that these marriages involve a higher risk for the transmission of faith to their children. We should make sure our friends and family understand these risks when considering spouses and should provide support to those whose faith may face higher risks.

If you are in a mixed-faith marriage yourself and this information gives you concerns about your children, your solution should be to work harder. If your spouse is not on the same faith team, your job is more difficult but not impossible. And for your unmarried or young children, have you talked about the importance of marrying someone who shares your faith? We might take for granted that our children will understand this, and hopefully our own marital love models this, but intentionally explaining and teaching this could be very important.

If you are trying to increase the chances of your children marrying a Catholic spouse (or finding one yourself), there may be a simple answer that helps: proximity. In reviewing the literature, Georgetown’s Center for Applied Research in the Apostolate writes: 

It is almost too simple. The likelihood that a Catholic will marry a non-Catholic is strongly and directly related to the likelihood that a Catholic will be in close proximity to [non-]Catholics. Social scientists have long understood that proximity is an essential factor in the process of romantic pairing. 

Catholic colleges and communities are more likely to generate same-faith marriages. 

In dioceses where Catholics make up only 10% of the total population, the average percentage of interfaith marriages celebrated in parishes is 41%. By comparison, this average is only 16% where 40% or more of the total population in a diocese is Catholic.

Note that this figure reflects interfaith marriages that are celebrated in a Catholic church and not all of those that are outside it. Things like economic opportunity, the weather, or even sports opportunities for kids may lead people to select where to live, but proximity to fellow Catholics may be more important for the future happiness and faith life of your children.

For clergy looking at this information, it may seem outside of their control. But there are certainly things they can do (beyond mentioning it in a homily). For example, a parish young adult group in my area organized a “Catholic speed dating night” and advertised it at other parishes. Priests and parish staff should also recognize that the children of mixed marriages, and spouses in those marriages, may be particularly at risk and consider providing extra care. The Code of Canon Law (1128) even singles out the needs of these people: 

Local ordinaries and other pastors of souls are to take care that the Catholic spouse and the children born of a mixed marriage do not lack the spiritual help to fulfill their obligations and are to help spouses foster the unity of conjugal and family life. 

At an absolute minimum, we need to keep these friends, family members, and neighbors in our prayers.