Who Did Cain Marry?

From Issue: R&R – March 2019

Skeptics argue that the Bible is a book of mythology, filled with inconsistencies and impossibilities. Clarence Darrow, the agnostic defense attorney in the famous Scopes Monkey Trial, scoffed at the Bible’s account of Cain finding a wife, asking William Jennings Bryan, “Did you ever discover where Cain got his wife?”1 Writing in Biblical Archaeology Review, Marry Leith argued that the text implies there must have been “other people ‘out there’ when God created Adam and Eve” from whom Cain picked a wife.2 Genesis 3:20, however, indicates that “all living” descended from Eve. If God created only Adam and Eve, and all other humans came from them, and Eve had only birthed Cain and Abel by the time Abel was murdered, who was Cain’s wife (Genesis 4:17)?

First, as discussed elsewhere,3 Genesis 4 gives several indications that a significant amount of time likely passed between the birth of Cain and Abel and the murder of Abel. If humanity was being fruitful and multiplying as God commanded (Genesis 1:28), it is reasonable to assume that Adam and Eve were not waiting many years before conceiving their next child. Genesis 5:4 indicates that Adam and Eve did, in fact, have “other sons and daughters” which are not listed in the text. If they had a single child every two years (i.e., no twins), and their children began marrying at the age of 19 and immediately began having children as well, there would have been roughly 300 people on the Earth by the time Cain was 1004—a plausible age as to when Cain may have killed his brother.5 Cain likely married either a sister or niece.

Some see a problem with that explanation, as it implies that Cain (and many others) were forced to commit incest—an illicit union in God’s sight. God’s law concerning incest, however, was not instituted until the Law of Moses came into effect (Leviticus 18), likely at least 2,500 years after Creation. It is generally assumed that the reason God outlawed incest at that point was due to the state of the human genome by the time of Moses. Incestuous relations significantly increase the likelihood of birth defects, as well as deleterious psychological problems.6 A child inherits 23 chromosomes from each of his parents. By having children with close relatives, many of those chromosomes are duplicated in the offspring—including those genes that are deleterious, rapidly increasing the odds of major physical problems.

When God created Adam and Eve, however, their genomes were pristine—without defect. Duplicate chromosomes would not have caused the defects observed today. After Adam and Eve were evicted from the Garden, denied the “healing effects” of the Tree of Life, and were subjected to the cursed Earth (Genesis 3:14-19), their bodies and genomes would have begun to suffer the effects of entropy in earnest. The Universe, and everything in it, is growing “old like a garment”—gradually decaying (Psalm 102:25-26). Ultraviolet and other forms of radiation (especially radiation from the Flood), as well as other mutagens and DNA replication errors have increased the accumulation of mutations in the genome. After over two millennia of genetic entropy, by the time of Moses the number of mutations within the human genome would have begun to make incest a dangerous practice.

Cain would have married a close relative. However, as would be predicted if the Bible is inspired by the God Who created the genome, and therefore knew of the growing dangers of incest long before humans had discovered the genome, God asserted Himself at the right time and prohibited the dangerous practice that He had previously sanctioned.


1 “Scopes Trial: Excerpts from the Court Transcripts,” Day 7,

2 Mary Joan Winn Leith (2013), “Who Did Cain Marry?” Biblical Archaeology Review, 39[6]:22, November/December.

3 Eric Lyons (2013), “Does Genesis 4 Indicate that God Specifically Created Others Besides Adam and Eve?” Apologetics Press,

4 NOTE: If the lifespans of the 300 were roughly that of the patriarchs of Genesis 5, death from old age would not have occurred by that point. It is possible that some of the 300 died from other causes, but it is also likely that children were being born sooner than every two years and that twins were common since God wished for the Earth to be filled (Genesis 1:28; 9:1). Regardless, even if half of the 300 had died, Cain still would have had dozens of possible marriage candidates.

5 Lyons.

6 J. Henderson (1983), “Is Incest Harmful?” Canadian Journal of Psychiatry, 28[1]:34-40; Hal Herzog (2012), “The Problem With Incest,” Psychology Today On-line, October 11,

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