Did incest populate the planet?

Painting of King Charles II of Spain
EXTINCT. Childless King Charles II of Spain (1661-1700), disabled from birth perhaps by genetic disorders, was the last of the royal Habsburgs—a family famous for keeping it all in the family…consolidating their power by marrying close relatives: first cousins, uncles to nieces, that sort of lovin’. The family became recognized for the Habsburg Lip, with its protruding jaw. Painting by Claudio Coello (1642-1693) / Wikimedia.


It comes from Debbie Baker Coffman, a redheaded friend of mine from long before gray hair started sprouting on our heads. She gets a free book for asking the question politely.

Here’s her question:

How was the earth populated in the beginning? Do you think God created more people than just Adam & Eve after they sinned? Otherwise, how could God expect brothers and sisters to reproduce?

My answer, up front, is I don’t know and I don’t much care. But I’ll tell you what the Bible experts say.

I don’t mean to be mean, certainly not to a friend. But as far as I’m concerned, this is one of those multitude of Bible questions that Bible experts wrangle over. When the dust finally settles and they’re sitting dirty-faced and spent from all the tussling with each other, all they’ve got is thin air and theory.

When incest was a good thing

Wrangling for the thin air of the tradition-minded are Bible experts who say the story of Adam and Eve is a news report from long ago: In the beginning, there was one family.

Brothers loved their sisters and sisters loved their brothers. Naked. And in ways that would pop the top off a yuck meter.

If we guys could measure gross by the bucket of dog vomit, on a scale of 1 to 5 buckets, having a kid with our sister or with our daughter would require an extra bucket—which we would personally fill.

Besides, inbreeding with someone as close as a brother or sister makes more sick kids than outsourcing.

It’s a gene thing.

Like most of you, I have two sets of 23 chromosomes, I’m told. One set from Mom. One set from Dad.

I may have gotten a broken gene from Mom that leaves me vulnerable to skin cancer, as an example. But Dad’s version of that gene was in good shape. So all I am is a carrier.

If I marry someone from outside the family who has both sets of skin genes in good shape, our kids have a good chance of getting two sets of healthy skin genes.

But if I have kids with my sister, who also has Mom’s busted gene, our kids would have a 50-50 chance of getting two sets of busted skin genes. That’s bad news.

Tradition-minded scholars argue that this wasn’t a problem with the family of Adam and Eve because God don’t make junky genes.

“Adam and Eve, coming from the creative hand of God, had no such mutant genes. Therefore, marriages between brothers and sisters, or nieces and nephews in the first and second generations following Adam and Eve would not have been dangerous,”  Dr. Charles C. Ryrie, Basic Theology.

The Bible doesn’t say if God created other Adams and Eves. It does say they had more children. “After the birth of Seth, Adam lived another 800 years, and he had other sons and daughters,” (Genesis 5:4 NLT).

Some of the reasons tradition-minded folks take the story literally is because New Testament writers seemed to do it.

  • Luke traced the family tree of Jesus all the way back to “Adam…the son of God,” (Luke 3:38).
  • Paul wrote about Adam as though he was a real man, not a myth: “When Adam sinned, sin entered the world,” (Romans 5:12).

Evolution trumps incest

Some progressive-minded scholars read the Creation story as a myth.

Think “parable.” That might make this pill easier to swallow.

As this thin-air theory goes, the Genesis writer—whoever it was; this is an anonymous book—lived in a day when there were lots of creation stories getting pitched over campfires. The most famous stories credited gods from Egypt or Iraq with making the world.

With all this going on, the Genesis writer crafted a story to help people wrap their heads around an otherwise inconceivable package: the idea that God created everything that exists.

For Christians on this side of the wrangling, evolution is no deal-breaker. It’s quite the possibility—just another theory about how God did what only God could do: make a lot of something out of nothing or less.

Debbie, pick your poison.

Then go to church, drink the cup of heaven’s kindness, and trust in Jesus.

PS. For those interested, here’s a short interview I did at the annual Christian Booksellers conference.



  1. Steve Grisetti says

    This is an interesting blog, Steve! I’ve been working through Genesis, and I was taken a little aback by the preference, at many points, of blood relatives for spouses.

    I like the interview snipped too! It’s great to finally have a voice to go with your face.

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