Neko, Pius XII in Humani Generis, Aug. 1950, stated that Adam and Eve can be considered as figurative, but the event is primeval;  meaning that there has to be a first couple.  DNA tracing of the human genes determines that it is impossible for a first couple but multiple couples...that is what evolution and gradual descent with modification implies.  It seems that Pius accepted science with religious modification.  He was warned by LeMaitre, responsible for noting what is know called the Big Bang, not to use that as proof for God as first cause...the church could not afford another Galileo. :)