Why is every person under the curse of Adam?
Every person is under the curse of Adam because all are his offspring, born of his line, and thus sold under the curse, under old Adam. Paul says this, and it contrasts with Christ, whose blood system originated with the Father, making His blood divine and sinless.
Les teaches that the blood circulatory system of every human fetus originates with the father, and the mother's blood never courses through the child. This explains how Mary could carry Jesus without her blood flowing through His veins. Jesus' blood system originated with the Father, so it was divine and sinless. In contrast, all who are offspring of Adam are sold under the curse, under old Adam. Paul writes this, and Les notes that for the believer, old Adam is reckoned crucified and dead, though he remains an influence in the Christian life. When a person believes the Gospel, God saw them in Christ on the cross.