A recent Pew Research study found that if current trends of fertility rates, youth populations, and faith conversions continue, the population of Muslims "will nearly equal the number of Christians around the world" by the year 2050.
The study projected that by 2050, the world's population would increase to over 9 billion people, and that there would be some 2.8 billion Muslims (30 percent of the world population), and 2.9 billion Christians (31 percent).
Though the number of Christians will also increase, Pew projected that the increase of Christians will be a slower growth than that of Muslims.
Two of the major reasons for the rapid growth of Muslims are the fertility rates and the size of the youth population among Muslims.
"Globally, Muslims have the highest fertility rate, an average of 3.1 children per woman -- well above replacement level (2.1), the minimum typically needed to maintain a stable population," Pew Research stated. The fertility rate of Christians is at about 2.7; of Jews, at 2.3; of Buddhists, 1.6; and of Hindus, 2.4, the study added.
The study further found that the percentage of Muslim youth--younger than 15--was at 34 percent in 2010, which was much larger than the percentage of youth in the total population (27 percent). Hindus also had a large percentage of youth, at 30 percent in 2010. 27 percent of the Christian population in 2010 were youth, which was the same as the percentage of youth in the world's overall population. Having a large percentage of younger aged individuals projects that there will be higher rates of fertility in the near future, "with their prime childbearing years still ahead," Pew stated.
Religious conversion will also play a role in the population growth of religious groups, but the projections of conversions are difficult to measure and are unpredictable, according to Pew.
"In the projection model, all directions of switching are possible, and they may be partially offsetting," the study stated.
However, the study did project that Christians will experience the largest net losses from conversions.
"Globally, about 40 million people are projected to switch into Christianity, while 106 million are projected to leave, with most joining the ranks of the religiously unaffiliated," it stated.
