To remain the world’s largest religious group, Christians are going to have to heed Genesis and be fruitful and multiply—not just in the mission field, but also in the bedroom.
Christian births will be outpaced by Muslim births within 20 years, according to new projections released today by the Pew Research Center. Between 2030 and 2035, Christian mothers are expected to welcome fewer babies (224 million) than Muslims (225 million) for the first time in history.
By 2060, such growth will result in the global population of Christians and Muslims approaching parity—totaling 3.1 billion and 3 billion, respectively—with each tradition accounting for nearly 1 in 3 people on earth. Over the 45-year period, the Christian population is predicted to hold steady at 31 percent, while the Muslim population is predicted to rise from 24 percent today to the same level.
The new report extends Pew’s respected prediction of how Christianity and Islam will change by 2050. It also adds more detail about the expected impact of conversions, which don’t change the size of religious populations as dramatically as birth rates. (CT previously examined how babies will halt the Great Commission.)
“In different areas, you’ll see different factors, but a lot of the growth is through birth,” said Bert Hickman, senior research associate at the Center for the Study of Global Christianity (CSGC) at Gordon-Conwell Theological Seminary.
Currently, Muslim families are having more kids than any other religious group in the world, according to the Pew findings. Muslims around the world average 2.9 children; Christians come in second with 2.6. No other faith has birth rates high enough to grow faster than the population overall. Women without a religious affiliation have just 1.6 kids on average, and the “nones” are expected to shrink from 16 percent of the global population in 2015 to 13 percent in 2060 as a result.
The findings come as no surprise to experts. Those who study religious demographics have seen the statistics pointing to Christian and Muslims—not Christians and secularists—as the two groups contesting most for numbers in the decades to come.
But the projections do come as a surprise to some Americans, particularly the millennials who expected the world would get less religious and not more religious as they grew up.
About half of Americans correctly believe that Christianity is currently the largest faith in the world, while a quarter say Islam. A significant portion of religious nones (44%) and people under 30 (46%) believe that the religiously unaffiliated are bound to become the largest religious group in the world by 2050, Pew found. A little less than a third of Christians agreed.
Eric Kaufmann, author of the 2011 book Shall the Religious Inherit the Earth?, confidently answered the question in the affirmative; there’s simply not enough population growth among atheists and the non-affiliated to compete with the Muslim and Christian baby booms. By 2055 to 2060—as far out as the forecast goes—fewer than 1 in 10 babies born on the planet will be to religiously unaffiliated moms. Meanwhile, 7 in 10 will be either to Muslim or Christian moms.
Particularly in North America and Europe, Christians are correct when they notice people leaving their pews. Over the next few years, evangelism on a global scale is expected to result in a net loss for the church. About 5 million will convert to Christianity between 2015 and 2020, while 13 million will leave the faith, according to the Pew projections. That’s a bigger loss due to conversions than any other religious group. Most will become “nones.”