Author: Stephen Caesar
Subject: Apologetics
Date: 8/2/2003

One of the most frequent questions skeptics ask is, “Where did Cain get his wife?” The answer appears in Genesis 5:4: “And the days of Adam after he had begotten Seth were eight hundred years: and he begat sons and daughters.” During his long lifetime, Adam begat a large number of offspring of both genders, so there were plenty of women from whom Cain could have chosen a wife.

One might recoil at the thought that Cain married his own sister, but we must keep in mind that there literally was no one else available with whom to fulfill God’s command to “be fruitful and multiply” (Gen. 1:28). One might also raise the objection that such close inbreeding would cause serious genetic defects. This is only partly true. In Bradford, England, there is a large but extremely close-knit Pakistani community that practices inter-cousin marriages. There is a high rate of genetic defects among their children, often leading to early death, because of what geneticists call “deleterious recessives”—genes that carry potential dangers such as cystic fibrosis and sickle-cell anemia (Conniff 2003: 62).

However, inter-cousin marriages can also be beneficial. For generations, the hugely successful Rothschild banking family practiced intermarriage among cousins in order to preserve the family’s penchant for financial brilliance. The billionaire du Pont family in America practiced the same thing for the same reasons. Albert Einstein married his first cousin (Ibid. 60-2). In 2002, University of Washington genetic counselor Robin L. Bennett, president of the National Society of Genetic Counselors, reported in the Journal of Genetic Counseling that children of first cousins face only a 2-3% higher risk of birth defects than the rest of the population, making them about as risky genetically as babies born to women 41 years old. According to the science journal Discover, the negative attitude toward inter-cousin marriage is not based on science but is “a heritage of early evolutionists with misguided notions about the upward march of human societies” (Ibid. 62).

A 1960 study of first-cousin marriages in 19th-century England conducted by C. D. Darlington, a geneticist at Oxford University, showed that married cousins produced twice as many great-grandchildren as did outbred couples (Ibid. 63). This is directly relevant to the subject at hand: God’s order to the first humans was to “be fruitful and multiply,” which meant that high fertility was of the utmost importance, and Darlington’s study shows that inter-cousin marriage increases fertility. Why, then, the problem with the Pakistanis in Bradford? Discover explains:

“The consequences of inbreeding are unpredictable and depend largely on what biologists call the founder effect: If the founding couple pass on a large number of lethal recessives, as appears to have happened in Bradford, these recessives will spread and double up through intermarriage. If, however, Mayer and Gutle Rothschild [the founding couple of the inbreeding Rothschild dynasty] handed down a comparatively healthy genome, their descendants could safely intermarry for generations—at least until small deleterious effects inevitably began to pile up and produce inbreeding depression, a long-term decline in the well-being of a family or a species” (Ibid.).

Again, this is highly important to the subject at hand. Adam and Eve were created genetically perfect (Gen. 1:31), and were later made imperfect, as was the whole of Creation, by the Fall (Gen. 3:17-19, Rom. 8:22). Despite the Curse, Adam and Eve still must have had comparatively pure genes, which they passed down to Cain and his siblings. One generation was not enough time for the First Family’s genes to develop deleterious recessives, as would later be the case with the Pakistanis of Bradford. In other words, Adam and Eve were like Mayer and Gutle Rothschild, passing on relatively pure genes to their offspring, enabling those offspring to interbreed without much fear of lethal recessives wreaking havoc among their children. This is probably why the section of the Mosaic Law that deals with incest (Lev. 20:11-21) does not forbid cousins to marry.



Conniff, R. 2003. “Go Ahead, Kiss Your Cousin.” Discover 24, no. 8.


Stephen Caesar holds his master’s degree in anthropology/archaeology from Harvard. He is a staff member at Associates for Biblical Research and the author of the e-book The Bible Encounters Modern Science, available at