Does a sin gene exist?

Why does every descendant of Adam and Eve, except Jesus Christ, sin? Romans 3:23 says, “For all have sinned, and come short of the glory of God” (KJV), a theme reiterated in Romans 5:12: “Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned” (KJV). Commenting on Romans 5:12, one Bible commentary states, “When Adam and Eve rebelled against God, they not only lost their right to the tree of life, which resulted inevitably in their death and in the passing on of death to their descendants, but by sin also became depraved in nature, thus lessening their strength to resist evil…. Thus Adam and Eve passed on to their posterity a tendency to sin and a liability to its punishment, death.”¹

If so, then we have an inherited factor that puts us at odds with the Lord. Could this factor be a “sin gene”?

Genes

Genes determine our physical makeup, basic personality traits, and aptitudes. They have an enormous influence on who we are and how we behave. Genes are segments of the chromosomes that direct the production of proteins. As of 2003, we know the chemical structure of our genes spread out on 24 chromosomes.²

The human genetic material found in every cell (except red blood cells) consists of 3.164 billion units called nucleotides. All information required to form a human being resides in the order in which the four different nucleotides are linked together. A single gene contains thousands of nucleotides, and it codes for one or more types of protein. We each have approximately 30,000 genes, and know the functions of approximately half of them. However, genes occupy only 2 percent of our chromosomes; the other 98 percent is “non-gene” material whose functions are not well understood.

No one knows, though, how we go from proteins to behavior and personality, due in part to our sketchy grasp of brain function. All brain activity depends on the movements of nerve signals among millions of brain cells. At the junctures between nerve cells are gaps called synapses. Nerve impulses cannot pass from one cell to another without neurotransmitters. We suspect that the levels of these neurotransmitters (produced by proteins) likely determine how thoughts and feelings are generated.

The influence of genes is clearly seen in children when they show aptitude for art, music, math, etc.—all inherited from our ancestors. If, though, among our inheritance the tendency to sin exists, the big question is, Which of the 30,000 genes is responsible?

Genes and the Fall

After the six days of Creation, “God saw all that he had made, and it was very good” (Gen. 1:31, NIV). The Creator did an exhaustive review of all aspects of creation, from engineering, biophysical, biochemical, physiological, ecological, inter-relational, and sociological perspectives. We must assume, therefore, that there was nothing wrong with Adam and Eve when they came forth from the Creator’s hands. They could not have been created with a tendency to sin. So we look at the story of the first actual sin in search for clues to how the “tendency to sin” was acquired.

In the Genesis story of the Fall, the only consequence of sin was that Adam and Eve’s “eyes . . . were opened” (Gen. 3:7, NIV) and they became aware of their nakedness. In the absence of additional information, the “opening of eyes” is a difficult phrase to understand, but this in no way could imply a sudden lessening of Adam’s and Eve’s moral statures.

What happened to them after sin? Perhaps the Lord modified Adam’s and Eve’s genes so that now the first couple’s natures were sinful? Though possible, it is much safer to stay within the confines of the biblical narrative. Besides, do we really believe that the Creator of every good and wonderful thing would stoop to corrupt His own creation?

Whatever happened in Eden at, and after, the Fall, the notion that we have the compulsion to sin built into our very fabric is, indeed, troubling. The expression of genes is automatic (as the color of one’s hair or the shape of one’s nose); we didn’t choose them. Thus, where we have a “sin gene,” sinful behavior could be considered an irresistible and natural product of human nature. To make matters worse, some biblical texts seem to appear to bolster the argument for sin having a genetic basis. “Can the Ethiopian change his skin, / or the leopard its spots? / Neither can you do good / who are accustomed to doing evil” (Jer. 13:23, NIV). Fortunately, this text may also be understood to say that sinful behavior has become natural, like genetically determined characteristics, that we sin so easily; that makes more sense than seeing in the text evidence for a sin gene.

Are there sin genes?

In fact, the arguments against the notion of a sin gene are more impressive than the ones for it. If sin had a genetic basis, the Creator would be responsible for our sinful nature. Judgment for sinful behavior would constitute a mockery of justice. Even in earthly courts, aberrant behavior based on physiological causes is treated with compassion.

Additionally, there would be no known way to stop sinning and conversion could occur only with a genetic change. Ordinarily, we go through life with our inherited genes; behavior does not alter genes.³ Someone may argue that the Lord could, supernaturally, alter the sin gene. But, after such a change, the converted individual would be incapable of sinning again unless there would be another genetic change, only now in the wrong direction.

Also, if a sin gene were identified, then some form of gene therapy could cure this problem, as with any other illness caused by faulty genes. There would be no reason to think that God’s saving grace is needed for the reformation of character.

Then how could we explain the sinless nature of Jesus other than that He was either born without the sin gene, or was some kind of mutant, incapable of sinning? Neither option seems to be satisfactory, especially when the Savior must also be our Example.

If sin is not passed from one generation to the next via genes, the only other possibility would appear to be environmental influences. But the idea that sin is the result of external influences opens the way to excuse it. Besides, examples may be given to show sin can occur in a perfect environment (the Garden of Eden) or it need not happen in wicked environments (Jesus growing up in Nazareth).

Sin is sin only if it stems from free choice. If one’s sinful behavior is forced by irresistible internal or external forces, it may be excusable. For example, there is a genetically determined condition called Tourette’s syndrome. Attendant with this disease is a profane manner of speech. There are also documented cases where head injuries have lead to profound alterations in personalities in which previously responsible persons became unreliable and irresponsible.

Self-preservation

The all-pervasive nature of sin certainly suggests the genetic element, however unreasonable, of a sin gene. But what if sinful behavior was caused not by one, but by a combination of several factors, some of which were genetic? Moreover, the genetic components would not coerce sinful behavior but would merely predispose us to it, leaving us able to decide whether or not to sin.

Let’s consider the sinful gene called selfishness—the promotion of self-interest above the needs of others. In reality, this sin can be described as a warped expression of self-preservation with our instinct for the sin of self-preservation as the genetic factor. For many years I studied the biochemical changes in the bacterium Escherichia coli following exposure to the reducing substance thioglycerol. I noticed that thioglycerol inhibits or slows down the growth of this bacterium, and I decided to study how it happens.⁴ It turns out that the bacterial cell takes extreme measures to get rid of this offending substance.⁵ We now know that even in this simple bacterium there are networks of genes designed to defend the cell against the adverse effects of sudden bursts of heat, cold, external pressure, and numerous other environmental changes.⁶ In other words, the will to live is built into the very fiber of every organism by the Creator.

Adam and Eve, too, were created with this instinct for self-preservation.

So long as they were sinless, they felt secure in the friendly confines of Eden. But after their sin, as they were staring in the face of a suddenly uncertain future and eventual death, their instincts for survival quickly took over. They hid from the Lord and attempted to shift the burden of guilt away from themselves.

We, too, deal daily with our instincts to survive. This need prompts us in every situation we encounter to choose a course most advantageous for ourselves. But here we have a true choice: we are not compelled to benefit ourselves every time. On this level, followers of the Master are asked to practice self-denial for the sake of others.

In fact, says Paul, the Christian is called to die daily to self (1 Cor. 15:31), but even he, himself, confessed, “So I fi nd this law at work: When I want to do good, evil is right there with me. For in my inner being I delight in God’s law; but I see another law at work in the members of my body, waging war against the law of my mind” (Rom. 7:21–23, NIV).

The “law” Paul refers to here, may well be our ingrained selfishness but with no sin gene. Although we are genetically programmed to seek survival and comfort, we can control the extent to which we respond to our internal drives. We are not helpless pawns in the clutches of our genes.

Conclusion

As long as we are on this earth, facing uncertainties, aging, and death, we will have to deal with selfishness— a sin as pervasive as gravity. But as eagles are given wings to fight gravity (Isa. 40:31), the child of God has access to the Holy Spirit to overcome selfishness (Rom. 8:9–11). Only in the earth made new, when the prospects of life-threatening illness and death will be removed, will we be freed from the shadowy consequences of our instinct to survive.