What's the metaphor?
Yes.
A metaphor here is that Jesus Christ is like Adam. All will agree that He was not the reincarnation of Adam (a literal reading) but is metaphorically compared and contrasted with Adam.
1. He is like Adam as being the progenitor of a human race. In Adam's case it was a physical race. In the case of Jesus Christ, it is a spiritual race. There are some cults, such as the Unification Church (founded by Sun Myung Moon) which maintain that because Jesus is the new Adam, both are the progenitors of a physical human race.
2. He is unlike Adam altogether in regard to sin. Although Adam was created innocent of sin, he fell to sin in Eden and all of his progeny have inherited that nature, whereas Jesus was impeccable (incapable of sin) and did not sin so that his spiritual children have His nature. Some take this too far and insist that all Christians are incapable of sin while in this human body inherited from Adam.
3. He is unlike Adam in not having a wife. God created Eve for Adam, but Jesus never married and any who insist that He had to have been married to a wife (Mary Magdalene is frequently put forth as the New Eve by these people) are in serious error.
4. It is equally erroneous to insist that Jesus Christ must be married "spiritually". That definitely would leave His physical mother, Mary, out because it would constitute incest.
5. What, then, shall we think about the Bride of Christ, the Church? Is there some sort of physical marriage in heaven? Only if one becomes literal. God spoke of His wife, Israel, whom He divorced. When and how did God marry Israel, especially considering that Israel was a literal man? Is God a homosexual? Is Jesus Christ, as well as God, a polygamist in being married to a huge body of people, male and female?
This is just the tip of the iceberg of errors and heresies that have been taught and believed over the centuries of Christian history.