ROME – Over the past few days, the Vatican’s top body on life issues has caused a stir throughout the digital world for arguing that one of the church’s most influential, and controversial, magisterial documents in the past century is not covered by papal infallibility.

The larger debate began last month with the publication by the Pontifical Academy for Life of a new volume titled Theological Ethics of Life. Scripture, Tradition, Practical Challenges, which collects papers delivered during a conference sponsored by the academy last year.

Upon its release, the volume was criticized over the contributions of some theologians who argued for a distinction between moral norms, such as the church’s condemnation of artificial birth control, and the concrete pastoral application of those norms.

In the book, some theologians appeared to suggest that in certain limited circumstances, couples might be justified in choosing artificial contraception, or methods of artificial reproduction.

The academy defended the volume, saying its role as a pontifical academy is to facilitate dialogue among the top theological thinkers of the day about contemporary issues of key interest. Critics, however, argued that it was inappropriate for an official Vatican entity to include voices questioning some of the church’s core moral teachings.

Debate flared up again over the weekend about a tweet sent from the Pontifical Academy for Life’s official Twitter account arguing that St. Pope Paul VI’s 1968 encyclical Humanae Vitae – which reinforced the Church’s teachings on marriage and upheld its condemnation of artificial contraception – was not covered by the doctrine of papal infallibility, meaning it can be subject to change.

One of the Catholic Church’s most controversial doctrines, papal infallibility insists that the pope in speaking ex cathedra is preserved from error when he teaches on matters of faith and morals.

In their Aug. 6 tweet, the Pontifical Academy for Life argued that Humanae Vitae, and therefore its teachings, do not fall under papal infallibility, and that this was affirmed by Archbishop Ferdinando Lambruschini, a moral theologian who taught at the Pontifical Lateran University, during the July 29, 1968, news conference presenting the encyclical to the press.

In response to the wave of backlash to their Aug. 6 tweet, the Pontifical Academy for Life Monday put out a statement on Twitter defending the publication of last month’s volume and reiterating their assertion that Humanae Vitae was not covered by papal infallibility, but the tweet containing that statement was later deleted.

Ever since Humanae Vitae first appeared in 1968, there’s been an active debate over exactly what level of authority it possesses, and, by implication, whether one can dissent from it and still be a good Catholic.

In general, conservative theologians say no, insisting the mere fact that the ban on birth control has never been formally declared as infallible doesn’t mean it’s not.

They point out that such declarations generally are reserved for matters of faith, not morals – for instance, the dogmas of the Immaculate Conception and the Assumption of Mary, the only examples of formal assertions of infallibility in the last 150 years – and that just because no pope ever proclaimed the church’s moral teachings against lying or stealing as ‘infallible’ doesn’t mean they’re up for grabs.

In 1997, a Vatican office termed the ban on birth control “definitive and irreformable.”

Liberals, on the other hand, insist that had any pope since Paul VI wanted to declare Humanae Vitae infallible he could have, but none did.

They also point out that a 1998 apostolic letter by John Paul II called Ad Tuendam Fidem expanding the scope of infallibility to include the “ordinary and universal magisterium,” meaning something taught by the popes and bishops even without a solemn declaration, didn’t refer to contraception, and neither did an accompanying commentary by then-Cardinal Joseph Ratzinger, the future Pope Benedict XVI.

The status of Humanae Vitae, therefore, is still widely contested, and if this latest digital dust-up with the Pontifical Academy for Life is any indication, it probably will be for some time.

Follow Elise Ann Allen on Twitter: @eliseannallen