Patheos answers the question:

Is Christianity Declining in Numbers?

Christianity is currently the largest religion on the face of the planet. Islam is the second largest. However, recent studies show that the faith founded by—or attributed to—Jesus of Nazareth is in danger of losing that coveted #1 spot for a number of reasons.

Fertility Rates

Stereotypically speaking, in the mid-20th century, if you saw a large family with a half-dozen kids living somewhere in the United States, you might wonder if they were Roman Catholic or members of The Church of Jesus Christ of Latter-day Saints (aka “Mormons”). However, today, fertility rates among Christians are on a sharp decline in much of the world. And that lack of reproduction has caused a precipitous decline in the number of practitioners of Christianity. One source pointed out,

“Indeed, fertility differences between religious groups are one of the key factors behind current population trends and will be important for future growth. Globally, Muslims have the highest fertility rate of any religious group—an average of 2.9 children per woman, well above the replacement level of 2.1, the minimum needed to maintain a stable population. This fertility advantage is one reason why Muslims are expected to catch up with Christians in absolute number and as a share of the global population in the coming decades.”

Elsewhere we read: “More than a third of Muslims are concentrated in Africa and the Middle East, regions that are projected to have the biggest [future] population increases.” Thus, as Christians have fewer children and Muslims continue to have more, Christianity will lose its foothold as the largest faith in the world—and Islam will most likely pass it up (by the mid-21st century). One recent piece on fertility rates and religion warned: “Christianity is aging, younger generations are having fewer children, and without a great influx of new members, thousands of churches will close over the next few decades.” The consequences of this on the size of the Christian tradition are obvious.


Christianity used to be a religion that aggressively proselytized non-Christian to the faith. This practice was grounded in Jesus’s Christ’s “Great Commission.” As is well known, during His post-resurrection forty-day ministry, Jesus brought His apostles together and admonished them as follows:

“Jesus came to them and said, ‘All authority in heaven and on earth has been given to me. Therefore, go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.’” (Matthew 28:18-20)

Thus, Jesus commanded His followers to preach the good word, bring people to Christ, baptize the unbaptized, and teach the world the importance of “obeying” God in “everything” He had “commanded.” Today, there are still traditions (like Latter-day Saint Christians and Jehovah’s Witnesses) who continue to emphasize proselytizing. However, the largest Christian traditions (e.g., Roman Catholics and Eastern Orthodox Christians) don’t do much in the way of proselytizing—certainly not on the scale that they once did. Some low-church Protestant denominations proselyte, but not to the degree that Catholicism once did—nor in the same official and systematic manner. Additionally, Christians used to feel more comfortable about speaking openly about their religion—and living it in very public ways. But that tends to be less the case today. However, Islam—which is said to be the “world’s fastest growing religious group”—tends to be lived (by its practitioners) much more openly, and Muslims still seem quite comfortable sharing their faith and freely giving copies of the Qur’an to interested people of other faith traditions. As a result, Islam is growing, and Christianity is shrinking.


Some outside of Christianity, and many former practicing Christians, find the faith unattractive—and for various reasons. This can cause the formerly active practitioner to withdraw. But it also dissuades outsiders from joining.

One point often made is that Christians seldom live the teachings of Jesus. Outsiders sometimes see them as hypocritical. For example, in his book The 100: A Ranking of the Most Influential Persons in History, Michael H. Hart put Jesus as number three, behind Muhammed and Sir Isaac Newton. He explained: “If [the principles He taught] were widely followed, I would have had no hesitation in placing Jesus first in this book. But the truth is that they are not widely followed. In fact, they are not even generally accepted.” Thus, outsiders are put off of Christianity by the bad behaviors of its members, thereby reducing potential conversions. Christians are, in many cases, not living the teachings of their faith, which often leads to religious inactivity and eventual loss of commitment to (or belief in) one’s previous faith tradition.

For others, particularly younger people, Christianity is less attractive because it has so many “commandments.” Individuals today seem less receptive to authority figures, monolithic commandments, and someone or something telling one how to live his or her life. Genzennials, who often dislike authority and rules, are more prone to leave or are less inclined to convert (than were their parents or grandparents) when they look at Christianity’s many commandments, authority figures, and rules for life. These simply don’t appeal to them.

Similarly, because much of public discourse today is about inclusiveness, a number of Christian denominations have struggled to retain members—let alone convert new ones—because people often perceive the Christian faith as one which relegates so much of the world’s population to hell. Of course, that may be more perception than reality—but it is a widely embraced perception that is influencing the long-term viability of the faith. Thus, people sometimes leave or do not convert because they feel like the main message of Christianity is, “If you’re not one of us, you can’t go to heaven.” That lack of inclusivity (in some denominations) is more bothersome to people today than it was in times past.

In October of 2019, the Pew Research Center released the results of a study, in which they determined that Christianity in the United States was declining at a “rapid pace.” In one decade, thirty million Americans left Christianity. Similarly, in April 2019, a Gallup Poll indicated that there had been a 20% decline in “church membership” since 1999. Similarly, in Europe, more than 3 out of every four Christians do not attend our participate in Christianity in any meaningful way. Only about 22% of Christians (living in Europe) still practice their faith. One article on our website points out:

“Christianity grew in the early centuries because people truly lived out their faith; they put it into practice, working for the common good. Those in need experienced the love of Christ coming to them from Christians. This has been lost today as Christianity is often seen, not as the religion of love and affirmation, but the religion of legalism and denial. Christians have truly lost the spirit of the Sermon on the Mount, and in doing so, it is no wonder Christian adherence is in the decline. Pope Francis is right in his pastoral concerns. What he is promoting is exactly what is necessary for Christianity today. If we do not want to lose more adherents, but rather, regain those we have lost, we will listen and begin to truly make Christianity as it ought to be.”

Thus, there are lessons to be learned. If Christianity keeps the status quo, its decline will continue and, though it is seeing decent growth in East Asia and sub-Saharan Africa, in most predominantly Christian nations, the faith tradition attributed to Jesus is on the decline and, by all estimates, will most likely not be the largest world religion as of the mid-21st century.

5/14/2024 8:54:19 PM
Alonzo L. Gaskill is an author, editor, theologian, lecturer, and professor of World Religions. He holds degrees in philosophy, theology/comparative religion, and biblical studies. He has authored more than two-dozen books and numerous articles on various aspects of religion; with topics ranging from world religions and interfaith dialogue, to scriptural commentaries, texts on symbolism, sacred space, and ritual, and even devotional literature.