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Is Incest a Sin?

cain and abel wives

Most Evangelicals believe that the earth was created 6,023 years ago, and the first two human beings on the planet were Adam and Eve.

Adam and Eve had two sons, Cain and Abel. It is assumed that Adam and Eve also had daughters who are not mentioned in the Bible. The reason this is assumed is that Cain and Abel had wives and children. The question then that must be asked is this: where did Cain and Abel‘s wives come from? Since there were no people on earth before Adam and Eve, the only answer is that Cain and Abel‘s wives were their sisters.

The Bible is clear: incest is a sin. If God is a moral being, absolute perfection, explain why he used incest to propagate the human race. Doesn’t this mean that God broke his own moral commandments? If God is against homosexuality, fornication, and adultery — sins which lead to eternal damnation and Hell — as Evangelicals say he is, why would God ever condone or use incest as a means to advance his purpose and plan?

When Evangelicals are asked about why God used incest to propagate the human race, they typically give one of three answers:

  • Mystery — we just don’t know.
  • God’s ways are not our ways, and God‘s thoughts are not our thoughts.
  • God used incest for a time, and once the human race was growing, he banned incest, calling it a grievous sin (only to allow it again after the Flood for a time with Noah’s family).
  • God had not yet given the command against incest (or rape, adultery, fornication, bestiality, etc).

Answering the question, “why is incest wrong?” Christian Fundamentalist “Dr.” David Tee (known in real life as David Thiessen) wrote:

Because God decided to make it wrong at the right time when genetic deformities will arise and ruin his creation. This may seem like a flippant answer but it is not. God was protecting his creation from the ills that come from inbreeding.

To illustrate this sexual harassment was recently made illegal but all those who practiced sexual harassment prior to that event did nothing legally wrong. You cannot judge or condemn people (or God) based upon actions after the fact. In other words, the people who did sexual harassment when it was legal, did not commit illegal or wrongful acts. They are still innocent people even though eventually the act was declared illegal.

Tee states, “this may seem like a flippant answer.” Ya, think? Either incest is immoral, or it’s not. Either God is omniscient, omnipresent, and omnipotent or he’s not. Supposedly, God is sovereign. He knows everything from beginning to end. If this is so, wouldn’t have God known that there would be genetic birth defects? Couldn’t God have manipulated human DNA to eliminate this problem? Or better yet, couldn’t he have created numerous families, each with unique DNA? Instead, the moral architect of the universe used behavior he says is sinful to propagate the human race.

When you believe the Bible is the inspired, inerrant, and infallible word of God, such questions pose all sorts of problems for you. When you believe the Bible should be read literally, and that the history and science found within its pages are true, you are forced to defend incest and all sorts of immoral behavior. When you believe God’s moral law is absolute, incest committed by Cain and Abel proves to be an insurmountable problem.

I was an Evangelical pastor for 25 years. The incest question bothered me the entire time I spent in the ministry. I could not square incest in the book of Genesis with God‘s commands other places in the Bible. I concluded this was a mystery, and that someday, in Heaven, God would reveal his reasoning for permitting incest for a time. This is a common hermeneutic used by Evangelicals to not answer hard questions.

Are you a former Evangelical? How did you answer the incest question? Please leave your thoughts in the comment section.


Bruce Gerencser, 65, lives in rural Northwest Ohio with his wife of 44 years. He and his wife have six grown children and thirteen grandchildren. Bruce pastored Evangelical churches for twenty-five years in Ohio, Texas, and Michigan. Bruce left the ministry in 2005, and in 2008 he left Christianity. Bruce is now a humanist and an atheist.

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  1. Avatar
    Neil Rickert

    I was never troubled by the incest question. But that’s because I took the Adam & Eve story to be a fable. I’m still puzzled that some people take it as literal history.

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    I started having a problem with this when I was 12. I asked a Sunday school teacher about it. She was obviously flabbergasted, but her explanation was, there were other people in the Bible, they just weren’t mentioned because they were not important. As in a novel, a city may have a million people, but the story only focuses on a few characters. I understand giving this explanation to a child, but as an adult, I grew dissatisfied with Christianity’s refusal to address such discussions in a grown up setting. I read the Bible, and it never remotely mentions any other people in the beginning. It’s even worse with Noah. My favorite explanation to this problem is from the Jehovah’s witnesses. They claim incest was allowed because Adam was still perfect from Creation, and humans had not fallen deep into sin enough for genetic defects to happen. As humans became more sinful, incest had to be outlawed. And Noah’s family were allowed because they were righteous; the same reason God allowed them to live. Ridiculous, right? Like an all knowing God couldn’t foresee and prevent these problems.

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      Heh. I was never given the “there were other people” bit because there couldn’t have been, at least for the flavor of Christianity I was taught. Because if we weren’t all born of Adam, then we didn’t all inherit that pesky sin nature, and then there’s no need for Jesus to come rescue us from it. And if there’s no need for Jesus there’s no need for the church…

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    I answered it by not letting the ‘answer’ of “God allowed it, but only for a time” in my head at the same time as “God never changes his mind, he’s the same yesterday, today, and forever.” If those thoughts ever danced just a little too close together, a good dose of “His ways are higher than our ways” worked pretty well to tamp down the nascent cognitive dissonance. For the times it got a little too bubbly under the surface, there was always leaning not on my own understanding.

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    Strangely enough, the 10 commandments aren’t eternal. The Sabbath day commandment? Good only once mankind was created. Honoring your fathers and mothers? As far as we know angels don’t have fathers or mothers, so that is a new commandment for mankind. Worshipping a graven image? Who cares? Worshipping another god? Blah blah blah. Really the last 6 commandments are most meaningful, and yet are still not all-encompassing of all the many, many bad things that exist. But all the Jewish laws in the Torah are many, and some seem not at all suited to modern life. We could probably throw out the OT (which is what many Protestant churches do, at least figuratively) and keep mostly the Beautitudes and some other love emphasizing scripture.

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    Okay, so sexual harassment wasn’t actually ILLEGAL until whenever (very recently). But there’s such a thing as being a creep, making people feel uncomfortable and worse, and THAT has always existed. In Britain where I live, it was perfectly LEGAL until 1991 for a husband to rape his wife.

    This man’s desperate attempts to claim such men are “innocent” because there was no official law on the statute box are pathetic (but not unexpected.). Hell, it’s like these men have no moral compass and can only stop harassing and raping if there’s a rule about it put down in writing.

    • Avatar
      Bruce Gerencser

      Tee’s argument is horrific at every level. Nothing is wrong until it is “legally”wrong. Imagine the kind of world we’d live in if that was the case? No law/no responsibility, right? If you have not read Tee’s defense of Ravi Zacharias, please do so (on his regular blog). Ugh . . .🤬

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    Steve Ruis

    According to the Bible “And Cain went out from the presence of the Lord, and dwelt in the land of Nod, on the east of Eden.” That there was another “land” and it had “a name” and Cain found his wife there, indicates that the creation myth is about the creation of a people and not all people.

    This is not dwelled upon because it undermines the authority of the churches to lord it over all of us. If it is so, then that god’s commandments and whatnot only apply to the people he created. The Great Flood is therefore a massacre of peoples not linked to Yahweh in any way. If you think about it, it changes everything.

    Plus, the ludicrous excuse of the female children of Adam and Eve not being mentioned should be flushed down a toilet somewhere. Didn’t Eve have a name? Are there not whole books of the Bible named after females? Aren’t female characters mentioned all over the place (don’t mention Lilith, though, that is forbidden)?

    The people who make up BS responses to serious questions rarely think through what they are claiming, which often makes the situation worse than better. They just fling stuff against the wall to see if anything sticks, and if it does, they go with that.

    • Avatar
      Bruce Gerencser

      You make a good point about the “Land of Nod.” Another one of those “hmm” moments in the Bible. 😂

      Literalism and inerrancy force you to defend all sorts of stuff.

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    Hey Bruce.

    I believe this is where the incredibly complicated system of dispensationalism comes in. Early Genesis would have been the age of conscience (or government). By the time of Moses it was the age of law. If memory serves the people asked God for his law and (10 commandments). It was at this stage that incest was revealed as sin. God knew people couldn’t save themself and they were still saved by looking towards the sacrifice of the messiah (still sacrificing the lamb as a symbol of Jesus). In acts 17:30 I think Paul speaks about in time past God winked ‘at ignorance’, to a certain degree turned a blind eye.

    So the idea of the law was to show we can’t do it on our own, and we need a saviour (Christ). We’re under the dispensation of grace now but that does not mean we should abuse grace (numerous scriptures).

    Did Adam and Eve commit incest? Yes, but this was after the fall. The fall changed human bodies and the manner of pregnancy so prior to the fall it would not have been incest but something else.

    Apologies if I’ve missed something out, it’s been a while since I’ve had to defend a faith I no longer have 🙂

    • Avatar
      Bruce Gerencser

      Ah yes, dispensationalism. This makes perfect sense. 😂 I was a dispensationalist into my early 30s. I adopted a Calvinistic postribulational, amillennial view after that.

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    I am a creationist, but reject the notion that all humans descended from 1 man and 1 woman. I believe all of us descended from a small population of humans that existed alongside Adam and Eve

    • Avatar
      Bruce Gerencser

      Inquiring minds want to know:

      And this is better, how? Where did this other group come from? Who created them? When? How old is the earth? What evidence do you have for these claims?


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        When God caught and confronted Cain over the murder of his brother, Cain yells in fear, “My punishment is more than I can bear! I am being driven out of the land! Whoever finds me will kill me!”

        Who? His parents? Or Other children of theirs? Or were there other unrelated humans alive at the time? I think the last one is the most likely.

        I don’t see a God, who thunderously rails against any hints of sexual deviancy (to the point he threatens damnation against a man who even looks at a woman in lust) allowing a bunch of brothers, sisters, cousins, and grandkids running around committing incest against one another to populate earth.

        Humans have a natural aversion to having sex with immediate or extended family members. And we recoil in anger and disgust when we see people engaging in incest. And rightfully so.

        Fundamentalist Christians can’t seriously condemn homosexuality and then turn around and approve of polygamy and incest at the same time.

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    This is another example of why biblical literalism is completely untenable. You can’t say that a deity is omnipotent, omniscient, and immutable if it can’t even figure out a way to create maybe 10-20 sets of humans to procreate so the humans don’t have to resort to incest, then outlaw incest later because oopsies, genetic disorders.

    I still am amazed how so many people can put up with these obvious issues. And I was one of those people, scared into believing that garbage.

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    I agree that heterosexual monogamy between an unrelated man and woman is the best, most-stable, time-tested model for a family unit. But the problem is that the OT God himself redefined marriage multiple times by allowing Abraham, Jacob, David, and Solomon to take multiple wives and by (presumably) allowing a bunch of siblings and cousins to commit incest to populate earth.

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      Sorry, OT morality involves rape and murder. You can’t use the OT to hold up great moral values. I may be in a heterosexual monogamous relationship, but I have lovely relatives who are kind and loving and productive citizens, and they contribute a great deal to society. They are lesbians married to each other and quite lovely.

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    My favorite bit of the Creation Museum is the label that tries to explain the Cain’s-Wife incest issue–instead of just saying “God said it was OK then but it’s not OK now, God works in mysterious ways” there’s a lengthy pseudo-sciency paragraph describing how back in the day when humanity was young we hadn’t sinned a lot yet but now generations and generations of sinning mean that different people’s sins have accumulated in their genetic databanks and if two people with double recessive sins get together then that’s where birth defects come from. Or something like that. It made zero sense but they were trying So. Hard.

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      Elliot, that’s an incredibly rude thing to ask someone. If I did such a thing to a LGBT individual or couple, I would fully expect to be immediately and permanently dumped, because it’s none of my business.

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      I know lesbians and a trans woman fairly closely (family and friend). And being LGBTQ was something they were aware of as part of their being for a long, long time. The ones I know are: a professional engineer, a pastor/scientist, and a machinist. Hard working, decent people. They are fine the way they are. If you don’t like it, just go to your community that excludes them. Oh, you might come across LGBTQ people in your daily life, and you can put on a veneer of politeness while secretly judging and hating them. That should make you feel all righteous and godlike. Meanwhile, Christians of your type are eating themselves to death (gluttony), fornicating, committing adultery, raping children, gossiping, etc etc. And yet you all only care about homosexuality as a horrible sin. Guess what? I’m proud of my LGBTQ family and friends because they are awesome.

  12. Avatar

    Forgive me, that isn’t how I meant to ask the question. I am not a Christian and homosexuality is something I don’t know enough about to make a comment on or take a hard stance on.

    What I’m curious about is whether gays or lesbians experienced a past trauma or other trigger event that caused their sexual orientation.

    For instance, some combat veterans are triggered to become fearful and alert if they hear loud noises or bright, flashing lights.

    I haven’t met anyone who was gay or lesbian, so this is something I’m genuinely curious about. I mean no offense.

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    I’ve never committed adultery nor am I a glutton. I’m almost 29 and have never had sex, in fact. I am guilty of gossip so I’ll definitely be held accountable for that one.

    Has anyone here seen that video where Steven Anderson shrieks and rages about how he wants Bruce Jenner to die and go to hell?

    • Avatar
      Grammar Gramma

      Elliot – nothing “causes” someone’s sexual orientation, certainly not trauma. Perhaps you should meet some gay and lesbian people and have a discussion with them about how their sexual orientation “arose.” They will likely ask you when you decided you were straight (assuming you are). Perhaps they will lead you to the discovery that sexual orientation is not something one chooses.

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    MJ Lisbeth

    Eliot–I am transgender. I suffered sexual trauma (namely, abuse by a priest). But it didn’t “cause” me to become trans or “confuse” me about my identity: Rather, I knew much earlier that my gender identity didn’t align with what was on my birth certificate or the way I was being raised. I didn’t know the word “transgender” or even “transexual,” but I was indeed one, just as I was abused by that priest before anyone so classified his actions.

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    MJ Lisbeth

    In my youth, I committed a hate crime. It would be decades before that category was named or defined, but it doesn’t change the fact that I committed a crime against another person based on his (apparent) identitity.

    As an adolescent, I committed a gay-bashing. Now, I could say that I was acting out of rage against my own inability to conform to norms of the gender, and the place and time, in which I was being raised. I could also say that I was trying to show some guys I knew that I wasn’t a “faggot” or “sissy.” None of that changes the nature of my crime.

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    If a gay couple lived next door to me, I’d leave them alone and not bother them unless they made advances on me or did something that was absolutely grotesquely obscene in front of my family. But that goes for anybody, really.

    Personally, I don’t have a problem with gays or lesbians. I’m not bothered by another person’s sexual orientation. I’m on the fence regarding same sex-marriage.

    But a deeper part of me has a fear that the Abrahamic God, Hell, and the Bible’s warning against homosexuals MIGHT be real. Since I did attend Christian school from 2006-2008 and took some Bible classes in college. I’ve gone to church before and considered becoming a Christian, but ultimately never did.

    As for the Abrahamic God and Jesus, my feelings on them are mixed. Some positive. Some negative.

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Bruce Gerencser