Yaffah Batya daCosta summarizes “Two Seedism” as follows[1]:

The "Two Seed" theory is the view that the Serpent (in Genesis) did not tempt Eve with a fruit, but rather that the serpent seduced her, had intercourse with her and fathered her firstborn son, Cain.

One of the verses used as a proof text is the one that has Eve saying "I have gotten a man from the Lord" (interpreted to mean the Serpent) at the birth of Cain (Genesis 4:1). An obvious contradiction is the fact that just before this, it says, "... and Adam knew Eve" (in the biblical sense, i.e., they had intercourse). So, the Two Seed theorists propose that Cain and Abel were twins. They say that Eve did indeed have relations with Adam, but that she had just a bit earlier been impregnated with Cain by the Serpent. And, yes, it is genetically possible that fraternal twins can have different fathers.

But the rationale gets onto even thinner ice. You see, even if this were true, all of Cain's evil seed (i.e., his descendants) would have been wiped out during the flood. Ah … not so, say the Two Seed theorists! Because they further claim that Ham's sin against his father Noah was to "uncover the nakedness of his father" (Gen 9:22). This has been interpreted to mean that Ham had sexual relations with Noah's wife Na'amah, whom they further claim was descended from the Serpent seed line. This Na'amah is found mentioned only in Genesis 4:22 as the sister of Tubalcain. But Noah's marriage to this Na'amah is not mentioned anywhere in the Bible.

The theory says further that the child of this union was Canaan, and God's curse on him had more to do with Canaan being the product of an adulterous relationship, as well as being a descendant of the evil "Serpent seed" line through his mother, who had survived the flood.

All of Canaan's descendants then, literally and biologically the descendants of the Serpent, are the children of the Devil in this doctrine. Due to the intermarriage of Canaan with Ham's other descendants, all of the people from Africa are considered to be children of the Devil and, therefore, they have no souls (i.e., they're considered to be half human and half demonic).

This doctrine is not as innocuous as it might seem. Horrible things have been perpetrated against blacks and Jews due to this kind of thinking – like the outrageous torture-murder of a black man in Jasper, Texas, who was dragged to his death behind a truck by people who are alleged to subscribe to this theory. Many of the KKK over the years have accepted this doctrine and have taught contempt for blacks and Jews because of it.

This doctrine has also been used to promote a form of racial anti-Semitism. Since Judah is said to have married a Canaanite woman (Genesis 38:2), all of the descendants of the tribe of Judah (what some believe to be the Jews of today) are thought to be the literal descendants of the Serpent as well. The "Christian Identity" movement (of so-called Christians) makes much of this intermarriage between Judah and the Canaanite woman.

This movement teaches that Jesus (who is not of the tribe of Judah since His father is God) is speaking about the Serpent seed when he says that the Last Days would be like the days of Noah (i.e., abounding in wickedness from the descendants of the Serpent seed). A particular focus is on the "enmity" of the Two Seed lines (Genesis 3:15) in claiming that the sons of the Serpent-seed race (i.e., the Jews and blacks) have declared war on the white race (i.e., the sons of the woman). Also quoted (out of context) are verses in the Book of Revelation, which mention something called the "Synagogue of Satan."

”Two-seedism” looses sight of the biblical doctrine of the superiority of faith over ”birthright”. Christ is shown in Heb 7:3 as foreshadowed by the high priest Melchisedek, as being ”...without father, without mother, without descent, having neither beginning of days nor end of life, but made like the Son of God, [remaining] a priest continually.” It was Esau, who had the birthright, yet Jacob[2] had faith (interest in the covenantal blessings). The Gospel of Christ introduces a new economy (or dispensation), where no longer “blood” (i.e. genetical factors which are beyond man’s choice), but faith in Christ makes one “chosen” or “elected” or “predestined”.

Without doubt genealogies have an utmost importance in the Bible. The genealogies in the Gospels of Matthew and Luke prove the kingship of Jesus and the necessity for the virgin birth. It was based on these that the pharisees should have been compelled to acknowledge Christ as legal King of the Jews. At the same time, however, various passages in the New Testament state explicitly that salvation is not due to genetic factors. The most explicit is Jn 1,13: who were born, not of bloods, nor of the will of the flesh, nor of the will of man, but were born of God. This new way of thinking, away from “genetics” and towards “choices made by faith” is foreshadowed in passages such as Isa 54,1 where biological infertility (or, for that purpose, inability to become married and have natural children, because one is executed, as was the case with Jesus Christ) are not a hindrance in producing “seed” – a new seedline based on faith. “He shall see His seed” in Isa 53.10 declares those born again by faith in Christ to be Christ’s children – we are of Christ’s “descent” by faith.

In Mt 3,9 Jesus is quoted as saying: ”And think not to say within yourselves, We have Abraham to our father: for I say unto you, that God is able of these stones to raise up children unto Abraham.” This shows that not an alleged or factual physical relationship with a genealogical line going back to Abraham will save one from hell (Mt 3,7-8), but being ”raised up” by God. God can raise up children unto Abraham from stones, that is, God can declare someone to be a child of the promise, short-circuiting all genetic factors. Salvation by race is impossible, salvation by grace is God’s way.

Ted Weiland from Mission to Israel (www.missiontoisrael.org) provides a detailed refutation of serpent seed theories[3]. He defuses the ”seedliners” appeal for an avoidance of a hermeneutical double morale, spiritualizing one thing and interpreting literally another[4], with the following thought:

... consider the option that Genesis 3:15 is referring to two spiritual seed lines within one physical seed line or group of people. Or to put it another way, one physical seed line with two spiritual outlooks on life: spiritual followers of evil and spiritual followers of good. Yahshua even warned of enemies from within one's own household or family - Matthew 10:36.

Serpent seed theories are used by adherents of such racist movements as British Isrealism and ”Christian Identity”[5] as well as of Jews with a peculiar kind of racism of theirs[6]. These theories also promote various kinds of pious forms of misogynism (hatred against women), to which purpose Gen 3:13 is alluded to.

Serpent seed theories loose sight of the biblical teaching that all men are equal before the Gospel. This teaching is seen in the following passages: Gal 3:28 There cannot be Jew nor Greek, there is neither bond nor free, there is no male nor female; for you are all one in Christ Jesus. Ro 2:29 but he is a Jew who is one inwardly, and circumcision is of the heart; in spirit and not in letter; whose praise is not from men, but from God. Ps 107,2-3: Let the redeemed of the LORD say so, whom He has redeemed from the hand of the enemy, and gathered them out of the lands, from the east, and from the west, from the north, and from the south. Col 3:11 where there is neither Greek nor Jew, circumcision and uncircumcision, foreigner, Scythian, slave or freeman, but Christ is all things in all.

W. H. Griffith Thomas writes[7]

...the unity of the race [is] the basis of all Bible doctrine (Rom 5, 21-21)

Romans 3 states explicitly that ” all have sinned and come short of the glory of God” (v. 23), that the whole world stands condemned before God: ”But we know that whatever things the Law says, it says to those who are under the Law; so that every mouth may be stopped and all the world may be under judgment before God” (v. 19). Therefore everybody has ”serpent seed”, everybody is born of Adam, not Satan, yet due to Adam’s Fall everybody is born a potential reproduction of Cain. 1. Jn 3:12 (a passage which ”seedliners” wield) can be understood in the light of this: Cain was wicked, because his works were wicked, not because he was of the Evil one. Jesus Christ then can be seen as the one who reinstaurates humanity, who gives everybody the possibility to make the Cain-element ineffective. As Jesus Christ is the only human being that God can accept, one becomes ”human” in God’s eyes only through faith in Jesus Christ and resulting rebirth through the Holy Spirit.

The apostle James testifies to the universality of humankind: ”By this we bless God, even the Father. And by this we curse men, who have come into being according to the image of God.” (Jas 3, 9). The biblical teaching of the universality of humankind goes against the notion of limited atonement. According to the Bible all men are created in God’s image, there are no people who are exempt from the possibility of salvation because they are ”counterfeit humans” who are actually serpent-seed-humanoids in human disguise

”Seedline” thinking has been lingering all during Church history and the great pedagogian Johan Amos Comenius seems to have been wrestling with it as well. In a chapter ”Schola Geniturae – School prior to birth”, in his famous ”Pampaedia”[8], he links the universal equality of humankind as created by God without exception to the notion of ”God’s seed”. He quotes Mal 2:15[9], saying that godly parents are ”seeking God’s seed”. Parents are to unite sexually in order to procreate children ”for heaven”, for God. In the same breath he makes it clear that for him all men are God’s seed, all men are destined for eternity. ”Whoever is born in an honorable way by honorable parents, is born in a good way.” For Comenius, the possibility for ”seeking God’s seed” is not dependent on genetic factors, but on the faith of the parents, who consciously make a faith-based choice, namely to raise their children in the fear of God. Thus for Comenius the ”seed of God” is within the reach of all of humankind – if only they actively opt for godliness in their parenting and child-rearing. All men are equally created and can be traced back to Adam, however, not all eventually become partakers of the divine seedline, because not all have faith.

Serpent seed theories are founded on exegetical fallacies. Ted R. Weiland writes [10]:

”If the Hebrew word translated "eat" in verse 17 is equivalent to sexual intercourse, then the same Hebrew word translated "eat" in verse 16 would have to represent the same thing. If the tree of the knowledge of good and evil was Satan or some humanoid of another race, then the trees in verse 16 would also have to represent the same thing. In other words, if the seedliner's interpretation of Genesis 3 and Genesis 2:17 is correct, then consistency demands that the seedliners admit that Adam and Eve were permitted by God to eat, that is, sexually cohabit with the other trees, that is, other satans, demons or humanoids living in the garden at the same time. Consequently, the seedliners must also admit that God was the originator of and even promoted spouse swapping for both heterosexual and homosexual activities. This is just one of those insignificant details that the seedline proponents fail to tell their prospective converts.”

“In addition, there is another problem with the seedliner's interpretation of Genesis 3:6 in that Adam was commanded by God not to partake of the fruit of the tree of the knowledge of good and evil prior to Eve's creation. Thus, Adam's sin could not have been having sexual intercourse with Eve since He was commanded against partaking of a tree that was already in the garden before Eve was even created.“

The implications for missions of serpent seed theories can be illustrated by means of the following quotes from a web-based article written by a ”seedline racist”[11]:

...is there any point of presenting to that wretched seedline the Gospel of Christ? If that enmity is perpetual, and God implies that it is, and Christ verifies that it is, then is there any point in witnessing the Roman Road to them? No, for this seedline will always be at war with Christ. They are not His sheep and they cannot hear His voice. His sheep know Him, and He knows them. It is obvious that any missionary efforts toward the Children of the Wicked One are doomed to failure, and a complete waste of time and money. Worse than that, it is an insult to our Christ and His ministry and truth. The worst insults to Christ have always come from the Christian humanists...... How can we identify Satan's Seed so as to withhold all missionary efforts and government foreign aid to them if we are unaware of what we have taught so far? How can we be able to guard against their deception and intrinsic treachery, if we hold the thought-theology that all men are created equal or that salvation is to be offered to everyone? Knowing now the enmity placed by God in Satan's Seed people, and its intended direction, where would you expect to find their lies to be directed the most heavily? Would it not be against Jacob's children, the Caucasian Christian people? Would it not also be in an effort to hide their origin and to pretend to be among the Seed Line of the Woman?...

...Since Chay's children are not descended from Adam, they were never placed under the Law of Moses. Thus, they are not under the jurisdiction of The Law, and lawfully they are not, and never were, sinners. Since that is true, why would they need a Saviour descended from Adam, their non-Kinsman, in either the spirit or the flesh? Do you see now the reason for the absolute futility of sending Christian missionaries to Africa, India and Asia? Those good folks are not under the penalty of the sin of the Garden or of the Law of Moses! Also, they are not the put-away-in-punishment sheep of the House of Israel... (bold print in original)