ROME — Since he became pope nearly two years ago, the world has become accustomed to Pope Francis’ folksy manner. Indeed, with his homespun anecdotes and off-the-cuff quips, the pope at times comes off more like a plain-spoken uncle than the leader of the world’s 1.2 billion Roman Catholics.

But with his latest choice of words — he said this week that Catholics should not feel compelled to breed “like rabbits” — the pope appears to have set a new standard for the papal vernacular, amusing to some and insulting to others.

Speaking to reporters Monday on a return flight from a weeklong trip to Sri Lanka and the Philippines, the pope made the remark about rabbits (“excuse the expression,” he added) and said Catholics should instead practice responsible parenthood, noting that various birth control options exist that do not defy the Church’s ban on artificial contraception.

But it was the rabbit remark that set the social media sphere aflame, mostly with bemused reactions. Photos and cartoons of bunnies — not all publishable in a mainstream newspaper — proliferated on Twitter.

Other users advised Catholics to “hop to it.”

In Italy, the pope invariably made front-page news: Most newspaper editors found the rabbit reference hard to resist. One commentator for the Turin daily La Stampa rechristened the pope “Father Rabbit,” and suggested that his remarks would go down in posterity as the “Sermon of the Rabbit.”

But some Catholics took offense.

Catholics for Choice, which opposes the Church’s ban on contraception, said Francis’ remarks were “particularly troubling because of the Catholic hierarchy’s continued global war on birth control and reproductive choice.”

The pope was responding to a journalist who had said that many Filipinos believed that overpopulation was contributing to the enormous poverty in the country, and that many Filipinos disagreed with the Church’s ban on contraception.

Citing the recently beatified Pope Paul VI, whose 1968 encyclical expounded on the Church’s opposition to contraception, Francis urged openness to life as a condition of marriage, but said that did not mean that Christians had to “make children in series.”