Pope Francis' plain-spoken populism has won rave reviews, g-suite manchester from people in the pews to the man in the Oval Office, but his pronouncements on everything from atheists to abortion have shaken some conservative and traditional Catholics.

Six months after he was installed on the Throne of St. Peter, the pontiff's comments in a series of interviews are being denounced in scattered corners as "reckless" or even "borderline heretical." One critic called him "the Joe Biden of our era."

"The whispers are rising," said Steve Skojec, 35, a father of six from Manassas, Va., who said a scathing blog post he wrote about the pope's recent remarks got 20,000 views, compared with the usual 500. "There are more and more people who are feeling uncomfortable."

The skepticism rides behind a wave of praise for the down-to-earth Argentine — applauded for choosing Jesuit simplicity over Vatican opulence, emphasizing the poor and tweaking the powerful, g-suite and checking stridency at the door when talking about gay marriage, contraception or whether non-believers get into heaven.

"Best pope ever" is a frequent appraisal on Twitter, and President Obama, a Protestant, told CNBC this month that he is "hugely impressed" by the rookie leader of the world's 1.1 billion Roman Catholics.

The broad-based adulation — only 4% of Americans in a recent poll had an unfavorable view of the pope — is vexing pockets of conservatives who want a harder line on core doctrine and who worry that even if Francis has not altered church teachings, his words will be misinterpreted or exploited.

"I'm very disturbed by these off-the-cuff, informal remarks," said Christopher Ferrara, a columnist for The Remnant, a Catholic newspaper that opposes many of the changes that accompanied Second Vatican Council in the 1960s. 

"In one sense, there's no harm because church teaching has not been changed, but in the other sense there is tremendous harm because not everyone understands church teaching," g-suite cardinal manchester added Ferrara, who is drafting a letter to the Vatican requesting clarification on some of the pope's positions.

He pointed to a Kansas women's clinic that posted on its fence a quote from Francis — saying Catholics should not focus only on hot-button issues like abortion and contraception — as a rebuke to protesters.