Polygenism Can Not Be Believed
Polygenism, the belief that Adam and Eve were not two individual persons from whom all human beings descended, is an idea which is condemned by the Catholic Church.
What about Pope John Paul II's recent message to the meeting of the Pontifical Academy of Sciences?
It is important to note that the Holy Father’s recent statements regarding evolution were his opinions, not part of the Ordinary or Extraordinary Magisterium, as they were not addressed to the universal Church. Humani Generis (Pope Pius XII's Encyclical of 1950), on the other hand, is part of the Ordinary Magisterium, and so does carry much more weight. Besides that, it does not seem that the Holy Father directly contradicted any of the the fundamental teachings in that Encyclical, but simply gave a more positive outlook on Evolution than the Encyclical did (which also said that it was not heretical to believe in Evolution). Humani Generis does explicitly condemn a belief in Polygenism:
37. When, however, there is question of another conjectural opinion, namely polygenism, the children of the Church by no means enjoy such liberty. For the faithful cannot embrace that opinion which maintains that either after Adam there existed on this earth true men who did not take their origin through natural generation from him as from the first parent of all, or that Adam represents a certain number of first parents. Now it is no no way apparent how such an opinion can be reconciled with that which the sources of revealed truth and the documents of the Teaching Authority of the Church propose with regard to original sin, which proceeds from a sin actually committed by an individual Adam and which, through generation, is passed on to all and is in everyone as his own.18
18. Cf. Romans, 5:12-19; Council of Trent, Session V, canon 1-4
"Adam" means "man" in Hebrew, so could that be what the word means here?
The Hebrew word 'adam has more than one possible meaning.
It means man in the sense of mankind (both men and women), it means man as distinct from woman, and the third meaning is the proper name Adam. The question of which meaning of 'adam the word here refers to, may be settled easily just by turning to the Septuagint. The Septuagint translates 'adam as Adam , so the meaning of the Hebrew here was obviously the proper name Adam, and not a collective noun.
Compare that to the way the Septuagint translates pere' 'adam in Genesis 16:12 agroikos anthropos , not Adam , since in this verse it was not a proper name. [He shall be a wild man: his hand will be against all men, and all men's hands against him: and he shall pitch his tents over against all his brethren.”]
This understanding of the name Adam is also backed up by St. Jerome’s Vulgate translation.