Cardinal Carlo Caffarra of Bologna has long been a vocal supporter of ''Humanae Vitae's'' teaching on the morally appropriate means of family planning. So it was noteworthy that Cardinal Caffarra recently conceded that, while ''Humanae Vitae's'' conclusions were true, its presentation of those truths left something to be desired. As the cardinal put it, "No one today would dispute that, at the time it was published, Humanae Vitae rested on the foundations of a fragile anthropology, and that there was a certain 'biologism' in its argumentation."

Which put me in mind of a document I discovered in 1997 in a dusty Cracovian library while ingesting copious amounts of antihistamines: "The Foundations of the Church's Doctrine on the Principles of Conjugal Life." Its somewhat academic title notwithstanding, that document represents one of the great "what if" moments in modern Catholic history.

The document was the final report of a theological commission established in 1966 by the archbishop of Cracow, Karol Wojtyla, to help him in his work on the Papal Commission for the Study of Problems of the Family, Population, and Birth Rate, inevitably dubbed the "Birth Control Commission" by the world media. According to one of the document's authors, Father Andrzej Bardecki, the Polish theologians on Wojtyla's commission had seen two drafts of an encyclical on conjugal morality and fertility regulation. One had been prepared by the Holy Office (now the Congregation for the Doctrine of the Faith); it strung together various papal statements on the issue without even mentioning Pius XII's endorsement of natural family planning. And that, Bardecki told me, struck the Cracow theologians as "stupid conservatism." The other draft had been sponsored by German cardinal Julius Doepfner; it represented a grave misreading of what God had inscribed in human sexuality "in the beginning," the Cracovians believed, and did so in a way that emptied individual choices and acts of their moral significance.

So: were the only options "stupid conservatism" or the deconstruction of Catholic moral theology?

The Cracovians didn't think so. They thought the truth of the Church's teaching about conjugal morality and fertility regulation could be presented in a humane and personalistic way: one that acknowledged both the moral duty to plan one's family and the demands of self-sacrifice in conjugal life; one that affirmed methods of fertility-regulation that respected the body's dignity and its built-in moral "grammar;" one that that recognized the moral equality and equal moral responsibility of men and women, rather than leaving the entire burden of fertility-regulation on the wife. In proposing this fresh presentation of classic moral truths in a delicate area of pastoral care, the Cracovian theologians drew on the pioneering work done by their archbishop, Karol Wojtyla, in ''Love and Responsibility'' -- work that Wojtyla, as John Paul II, would later develop in the Theology of the Body.

And so, what if? What if Paul VI had adopted the Cracovian approach to presenting the truths he taught in ''Humanae Vitae?'' What if the encyclical had been built upon a less formalistic, even abstract, view of the human person and human sexuality? What if ''Humanae Vitae'' had deployed a richly-textured and humanistic anthropology that was not susceptible to the charge of "biologism"?

1968 being the year it was, and the theological politics of the moment being what they were, there would still have been an uproar, I expect. But had the Cracovian report provided the framework for ''Humanae Vitae,'' the Church would have been better positioned to respond to that uproar.

The Catholic Church now has ample materials with which to make sense of, teach, and apply its settled convictions on the morality of marital love and procreation: the Theology of the Body; John Paul II's magnificent 1981 apostolic exhortation, ''Familiaris Consortio;'' the pastorally sensitive 1997 Vademecum for Confessors on the Morality of Certain Aspects of Conjugal Life. And we have a brilliant analysis of the effects of a contraceptive culture in Mary Eberstadt's ''Adam and Eve After the Pill'' (Ignatius Press), which is must-reading for every bishop attending the upcoming synods on the family.

Still, I wonder: what if?

George Weigel is Distinguished Senior Fellow of the Ethics and Public Policy Center in Washington, D.C.