Monogenism is significant to Catholics who believe it contradicts the Church’s teaching on original sin. That being the case, it deserves thorough examination.
I personally would have no difficulty with polygenism, but some Catholics would refute this on the basis that it contradicts the Church’s teaching on ‘original sin.’ However, was the belief we all descended from one human pair the divine truth the author of Genesis communicating? The Genesis account is a theological account concerning the origins of not one man, not a scientific one. Therefore, it should be read as such. The construction of the text of Genesis itself indicates the author uses the name ‘Adam’ to explain not the creation of one man, but the entire human race. In the original Hebrew ‘Adam’ is not just an identifier, but is used to describe what it is to be human. ‘Adam’ translates into English as ‘red’ or blood and ‘man’ in the plural sense. I wouldn’t be qualified to go into the construction of Hebrew nouns and verbs, or the literary construction of ancient texts. Maybe someone else here can. What I can say based on the findings of Catholic exegesist’s among others, is that the author uses ‘Adam’ in Genesis 2: 7 to represent the entire human race. In short, the author’s use of ‘Adam’ in the accounts creation and the fall represents not one man or one pair, but a group of humans in the plural sense.
Based on biblical scholarship, polygenism is compatible with the Genesis account. However, I would say it has implications for Church teaching on original sin if the Church has declared the belief that we descended from one human pair as a divine truth. One of my theology lecturers is a priest and I asked him if the Church teaches we all descended from one human pair. His answer was, the Church has never taught we all descended from one human pair. Exactly what happened and how in relation to original sin is unknown to us. Based on the Genesis account, Adam being the first man in a group of humans to be created committing the original sin, the rest of the group following suit and passing it on, or a group of humans all committing the same original sin and then passing it on, are both compatible with both Church teaching and Genesis. I suppose the argument now is, does the Church say the belief we all descended from one pair is a divine truth and must be believed or did they not?