Pope Francis is having a positive impact on the way Protestant pastors view the Catholic Church, new research has found.

According to LifeWay Research, nearly 40 per cent of American pastors said that they have a better view of the Catholic Church under the Pope's leadership, though half maintain that they do not value his opinion on theological matters.

Almost two-thirds, 63 per cent, said they see Francis as a genuine Christian and brother in Christ. Just over a fifth, 22 per cent, did not agree with this statement, however.

Nine out of ten pastors said that Catholics can be born again Christians, though five per cent said they could not.

LifeWay found that evangelical pastors are more sceptical about Pope Francis' faith than mainline Protestants. Just 58 per cent of evangelical pastors believe the Pontiff is a true Christian, compared to 80 per cent of mainline Protestant pastors.

Mainline pastors (57 per cent) are also more likely to say they value Pope Francis' opinion than their evangelical counterparts (36 per cent). Half of mainline pastors said the impact of the Pope on their opinion of the Catholic Church has been positive, compared to 30 per cent of evangelical pastors, 15 per cent of whom say their opinion has actually declined since Francis took on the role.

The research was undertaken ahead of the pope's landmark trip to the US this week, where his approval rating is high across the general population. Some commentators attribute Francis' likeability to his softer stance on issus such as homosexuality and abortion, and his evident faith in Jesus which has seen him advocate passionately on behalf of the poor.

Commenting on the findings, LifeWay executive director Ed Stetzer said: "Our sample itself – Protestant pastors – is named after the Protestant Reformation, so they are particularly interesting to survey. And the survey says that this pope does, indeed, have a 'Francis effect,' even on a group of people named for protesting the very faith the pope leads. The fact that some pastors don't see the pope as their 'brother in Christ' seems strange to many outside Protestantism and evangelicalism, I imagine," Stetzer added.

"However, the forerunners of most Protestant pastors – from Luther, to Wesley, to Spurgeon, to many others – certainly did not see the pope as their 'brother in Christ.' Within a few centuries, the pope has gone from 'anti-Christ' to 'brother in Christ' for a lot of Protestants."