Islam will reportedly become the world's largest religion 55 years from now based on recent projections, but the barbarous practices of the Islamic State could undermine the growth of the world's Muslim population, experts said.

According to a recent Pew Research Center study, Christianity and Islam will be near parity by 2050, with Christians expected to comprise 31.4 percent of the planet's population against 29.7 percent who follow Islam.

The study said Islam will grow more than twice as fast as any other major religion over the next half century because of a higher fertility rate in Muslim dominated countries.

However, Muslims frightened by the inhumane acts by the ISIS, which the militants claim they are doing in the name of their god Allah, are now questioning their very own faith, and presumably considering to leave it, CBS News reported on Friday.

This is backed by testimonies from missionaries working in the Islamic world who noted that more Muslims have converted to Christianity in the last 14 years since the devastating Sept. 11, 2001 terrorist attacks in the US. The number of converts in the recent period, they said, is greater than during the entire 14 centuries of Islamic history.

"Many Muslims are saying, 'If ISIS is Islam, I'm leaving.' Some are becoming atheists," said Brother Rachid, who hosts a Christian program reaching Muslims called "Daring Questions" in Arabic language. "There is a huge wave of atheism in the Arab world right now and many are turning to Jesus Christ. Islam was never faced with this crisis before."

"Islam is going to collapse," added Brother Rachid, whose father is a Moroccan imam who lived as a secret Christian convert for 15 years.

Pastor Fouad Rasho of Angered Alliance Church in Sweden, who has baptized more than a hundred former Muslims, maintained that ISIS causes many Muslims to come to Jesus.

"Every week I meet one or more persons who come to me and want to know more about Christianity and the Bible because they are very angry about being a Muslim. They don't want to continue to be Muslim," said Imran, who is also an immigrant from Syria.

Many converts keep their shift in religion a secret, fearing for their lives and for being an outcast. Imram (not his real name), a British college student from a Pakistani immigrant family, said leaving Islam is tough.

"If someone leaves Islam and becomes an apostate, he is thrown out of his family; his family will be the first ones to abandon him," he said. "His friends will reject him and he will be killed or he will be persecuted. A lot of my friends said, 'This is the last time I'm talking to you because you disrespected the prophet Mohammed, you disrespected Islam.'"