Jesus said, "I have not come do abolish the Law, but to fulfill it."
No, I don't adhere to the Ceremonial Law, etc. But, you can't understand the Gospel without understanding Genesis 3. You can't understand marriage without Genesis 1 and 2. And so on...New Testament doctrine cannot be understood apart from an understanding of the Old Testament...and particularly, the Book of Genesis.
While I agree that an understanding of the Old Testament will help one understand the New Testament, I do not agree that we can use the Old Testament as authority for doctrine in the church of Christ. As Christ said, He came to fulfill the Law. Once it was fulfilled, it was no longer binding (Galatians 3:24-25). Paul also tells us that the writings of the Old Testament "were written for our learning, that we through patience and comfort of the scriptures might have hope" (Romans 15:4).