Adultery—Justified by Evolution?

Our supposed evolutionary ancestry is often used by evolutionists to explain just about everything about humans. Well, a recent article blared this headline, “Cheating: Where Primal Evolution Meets Modern Opportunity.” The article asks this question, “Are unfaithful ancestors the reason why some people cheat?” In answering this question the article looks to research from a relationships researcher at a university in my home country of Australia. Apparently, he “believes the habits of early humans play a huge role in the decisions people make about monogamy.”

He says that, according to evolutionary thinking,

Our unfaithful ancestors reproduced with greater success than their monogamous counterparts. . . .

Consequently, humans have evolved a tendency to cheat on their partners.

Women gained a reproductive benefit from infidelity because having children with a range of different men increases the genetic diversity amongst her offspring.

Men benefit from infidelity by simply increasing the number of offspring they produce, which also increases the chances that at least some will survive.

So, he’s saying that some people cheat on their spouse because they have evolved the tendency to!

No, people do not cheat because we have evolved “a tendency to cheat.” People cheat and commit adultery because of sin (the origin of which is detailed in the book of Genesis)! After all, “The heart is deceitful above all things, And desperately wicked; Who can know it?” (Jeremiah 17:9). Instead of appealing to an imaginary group of human ancestors who passed along the tendency to cheat, we need to call sin what it is: sin! Sadly, our culture has a warped view of sin. Lately there have been more and more attempts to explain sinful behavior in light of our supposed evolutionary past. But when we start with God’s Word we get an entirely different picture. We were created in God’s image and are accountable to Him. Because He is our Creator, He sets the rules and He has made it clear in His Word that adultery is utterly sinful, “Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge” (Hebrews 13:4).

Now, what do Christians who have compromised with evolutionary thinking about the past do with research like this? Do they concede that our sinful tendencies are the result of our supposed evolutionary ancestry? Can they use this as an excuse to justify their behavior? Absolutely not! This isn’t what Scripture says. According to God’s Word, we sin because it is our fallen nature to sin,

among whom also we all once conducted ourselves in the lusts of our flesh, fulfilling the desires of the flesh and of the mind, and were by nature children of wrath, just as the others. (Ephesians 2:3)

For when we were in the flesh, the sinful passions which were aroused by the law were at work in our members to bear fruit to death. (Romans 7:5)

Now the works of the flesh are evident, which are: adultery, fornication, uncleanness, lewdness, idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies, envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God. (Galatians 5:19–21)

One of the problems with compromise in one area of Scripture is where do you stop compromising? If Christians accept the idea of human evolution, then why not accept the idea that our sinful tendencies are really just evolved tendencies? But this completely changes the Bible’s definition of sin and why we sin and face the penalty of death for our sin, “Therefore, just as through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned” (Romans 5:12). A belief in evolution strikes right at the heart of the gospel! (To be clear: there are Christians who believe in evolution and their salvation is not in doubt if they have placed their faith in Christ—but their compromised position regarding Genesis does undermine the authority of God's Word.)

As Christians, we need to be bold in standing on God’s Word and calling sinful behavior what it is—sin. We don’t sin because “evolution made us do it.” We sin because we are sinful people in rebellion against our Creator. But, praise God, He sent His Son, Jesus Christ, to “forgive us our sins and to cleanse us from all unrighteousness” if we will “confess our sins” (1 John 1:9). That is the good news of the gospel!

Thanks for stopping by and thanks for praying,
Ken

This item was written with the assistance of AiG’s research team.