A survey of British readers of Dan Brown’s “The Da Vinci Code” shows that reading the book causes people to believe its claims over those of the Bible.

Those having read the book are twice as likely to believe Jesus Christ fathered children and four times as likely to think the conservative Catholic group Opus Dei is a murderous sect, Reuters reported.

“An alarming number of people take its spurious claims very seriously indeed,” Austin Ivereigh, press secretary to Britain’s top Catholic prelate Cardinal Cormac Murphy-O’Connor, told the news service.

“Our poll shows that for many, many people ‘The Da Vinci Code’ is not just entertainment,” Ivereigh added.

English Roman Catholic monks, theologians, nuns and members of Opus Dei commissioned the survey from leading pollster Opinion Research Business.

The poll of 1,000 adults showed 60 percent believed Jesus had children by Mary Magdalene – a claim presented in the book – compared with just 30 percent of those who had not read the book, reported Reuters.

The group that commissioned the poll demanded that the movie version, set to debut Friday, should carry a “health warning.”

Ivereigh complained that Brown and film studio Sony Pictures “have encouraged people to take it seriously while hiding behind the claim that it is fiction.”

In the U.S., some Christian organizations have urged a boycott of the film, while other believers see it as an opportunity to talk to unbelievers about the claims of the Bible.

Many documentaries have been produced to debunk claims made in the book, including “Breaking the Da Vinci Code.”

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Previous stories:

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‘Da Vinci Code’ errors: A quick list, by Dr. D. James Kennedy

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