The early chapters of Genesis may be considered as allegory, of which it is safe to consider. However there is a problem. If you completely throw away the first few chapters of Genesis then you are also throwing away the concept of sin and of the fall. Sin, according to Genesis, entered the world through Adam (also an allegory representing human kind), rejecting the commandment and love of God.
So if you throw away these chapters with:
"Yeah, and the age of Earth is about 6000 years. Not all in the Bible should be taken literally."
You are throwing away the doctrine of sin and rebellion, and therefore of the need for forgiveness through sacrifice (the Old Testament concept) and the doctrine that Jesus Christ was the ultimate sacrifice and the atonement for sins.
Throw away the overall message of the first few chapters of Genesis, by not even accepting them as allegory, then Christ was not required and any doctrine of the immaculate conception fades into the darkness together with all other doctrines.
However, the writing of the New Testament are harder to throw away, but you still reject them, therefore proving:
I Cor 23
but we preach Christ crucified: a stumbling block to Jews and foolishness to Gentiles,
Edited by DougRichards, 09 November 2019 - 2202 PM.