I personally don't think that sin has anything to do with the blood, nor that there was anything inherently evil in the fruit that Adam was forbidden to eat. Concerning the fruit, God could have just as well drew a circle on the ground and say "Don't go into that circle!" If that had been the case, we would be arguing about the possibility that there was some portal of sin into the world, blah, blah, blah.
Man was created to rule under God (Gen 1:26-28). But that means that, by definition, Man had to have the choice to rule under himself, which would require a direct rule from God to break. God provided that in the TKGE. Now, I actually follow Geerhardus Vos at this point. Let me provide an extended quote from his
Biblical Theology (Eerdman's, 1948), pp.31-32.
Vos wrote:Thus we are led to the view most commonly held in the past: the tree is called the tree of "knowledge of good and evil," because it is the God-appointed instrument to lead men through probation to that state of religious and moral maturity wherewith his highest blessedness is connected. The physical meaning of the phrase has been transferred to the spiritual sphere. On this view the name does no prejudge the result. To attain to a knowledge of good and evil is not necessarily an undesirable and culpable thing. It could happen in a good way, in case man stood in probation, no less than in an evil way, in case man fell. The name is neutral as to its import. That this is so frequently overlooked is due to the prohibitive form which the probation-test assumed. Because man was forbidden to eat of the tree associated with the knowledge of good and evil, it has been rashly assumed that the knowledge of good and evil was forbidden him. Obviously there is in this a confusion of thought. The prohibitive form of the test has quite a different cause, as will be presently shown.
If now we enquire how the maturity designated as "knowledge of good and evil" was to be attained, either in a desirable or in an undesirable sense, regard must be had first of all to the exact form of the phrase in Hebrew. The phrase is not "knowledge of good and evil". It reads, literally translated: "knowledge of good-and-evil", i.e., of good and evil correlated, mutually conditioned conceptions. Man was to attain something he had not attained before. He was to learn the good in its clear opposition to the evil, and the evil in its clear opposition to the good. Thus it will become plain how he could attain to this by taking either fork of the probation-choice. Had he stood, then the contrast between good and evil would have been vividly present in his mind: the good and evil he would have known from the new illumination his mind would have received through the crisis of temptation in which the two collided. On the other hand, had he fallen, then the contrast of evil with good would have even more vividly impressed itself upon him, because the remembered experience of choosing the evil and the continuous experience of doing evil, in contrast with his memory of the good, would have shown most sharply how different the two are. The perception of difference in which the maturity consisted related to the one pivotal point, whether man would make his choice for the sake of God and of God alone.
Now, I find that to be an excellent understanding of the TKGE. It also goes a long way in explaining the sin nature that Adam fell into. He knew evil because he chose to experience it. How is this passed on to us? Gen 5:3 tells us that Seth was born in Adam's own image. As that image was now fallen, Seth inherited this fallen image. Thus, everyone "in Adam" reflects that fallen, sinful state.
Regarding this, Ryrie has an excellent discussion in his
Basic Theology (Moody Press, 1999; pp.221-222) under the subject of traducianism. Again, I'll provide an extended quote, beginning with the context on page 220.
Ryrie wrote:III. The Transmission of Man's Being
When Adam begat Seth, he became the father of a son in his own likeness, according to his image (Gen. 5:3). Though Adam was made directly in the image of God, his children were generated in Adam's image, which, of course, still bore God's image even after the Fall (cf. 1 Cor 11:7). Thus the transmission of man's being was and is through natural generation.
No one questions this as far as the material aspect of man's being is concerned. Our bodies come from our parents, and theirs for theirs, etc. But how is the immaterial aspect of man passed from generation to generation. To this question several answers have traditionally been proposed
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C. Traducianism
This view holds that the soul is transmitted along with the body through the process of natural generation. William G. T. Shedd cited three kinds of support for this view. (1) Scriptural: Hebrews 7:10 indicates a rational and moral act on the part of unborn Levi; Genesis 2:1-3 states that God rested on the seventh day of Creation because His work of Creation was finished. No fresh acts, like creating new souls, are indicated; and verse 7 does not allow for the breath of life to be breathed into anyone else other than Adam. (2) Theological: creationism places God in the position of creating a perfect soul (He could not create a sinful one), then having it fall in the case of each newborn infant. The case of the sinless Christ is in every respect an exception and not the pattern for deciding the question. (3) Physiological: : man is always seen as a union of soul and body; therefore, it is more natural to consider both the psychical and the physical as developing together.
In summary, as I see it, when Adam sinned he experientially knew evil. Therefore, by definition, he no longer was the perfect reflection of God, looking to please his own self rather than to please God. Seth, and everyone after him, was born with that same fallen image. This is because this image--indeed, this condition--is passed on from parent to child through natural generation.
My view, anyway . . .