Pope Pius XII taught quite definitely in the encyclical Humani Generis (1950) that Adam and Eve were real human beings, the first parents from whom all of mankind has descended; they are not symbolic representations of mankind as a whole, and there were no other human races existing on the Earth from whom human beings could have descended. To hold otherwise, he declared, is to endanger the doctrine of Original Sin. He reiterated that the rational souls of Adam and Eve were divinely implanted by God in acts of Special Creation, and he reaffirmed the teaching of the Church on Original Sin:
"Sin actually committed by an individual Adam and which through generation is passed on to all and is in everyone as his own." 16
In view of truth known from Tradition and highlighted by Cardinal Ruffini, why did Pope Pius XII even allow any discussion about the possible evolution of Adam's body, as though human Evolution could somehow be true? What need was there for further discussion - surely, enough was known already from Tradition? One can only speculate. Since "Evolution" is still today the subject of confusion and conflicting definitions and mechanisms, and the model of DNA was not even fashioned until three years later (1953), perhaps the Pope in 1950 opted for caution and in-depth clarification from scientists, not anticipating that his encyclical would soon be so blatantly distorted.
Although he may have inadvertently left an opening through which Modernist concepts could penetrate into Catholic consciousness, Pope Pius XII did not give the impression that he believed Evolution to be compatible with the Faith. His encyclical Humani Generis (dated August 12, 1950, and appropriately subtitled, On Certain False Opinions Which Threaten to Undermine the Foundations of Catholic Doctrine) was issued in response to the danger posed by evolutionists (such as Teilhard de Chardin) who were pushing pantheism. Perhaps the Pope did not anticipate the lengths to which Modernists would go in trying to overturn official Catholic doctrine, but he certainly had no illusions about the danger of Evolutionism: