Mythical Creation Science: Who was Cain's Wife?

A common problem pointed out by people who can read is that Cain's wife came out of the blue. Ken Ham himself decides to tackle this problem himself in Chapter 6 of The New Answers: Book 1.

The Problem:
In Genesis 4, Adam and Eve have sex and give birth to Cain and Abel.  They both offer sacrifices to God.  God likes Abel's sacrifice, but not Cain.  Cain gets mad and kills Abel.  God banishes Cain.  Cain has sex with his wife and they have kids.  Eventually, Adam and Eve have another son they name Seth.

The problem is pretty obvious.  Genesis 4 lists three children born of Adam and Eve: Cain, Abel and Seth.  Cain found a woman somewhere - where did she come from?

Standard non-YEC answer:
The answer that I grew up with was that all of the Biblical stories before Abraham were myths.  The purpose of the myths were to explain our relationships with each other and with God.  For example, no matter how angry you are, you shouldn't kill your siblings is the basic idea behind the story of Cain and Abel.

YEC answer:
 First, they quote Genesis 5:4 to prove that Adam and Eve had lots of children: "After Seth was born, Adam lived 800 years and had other sons and daughters." Of course, Ham is very careful to avoid the fact that Seth was born after Cain killed Abel and Cain had had several children with his wife.

For now, let's go with the idea that Adam and Eve did have lots of other kids after Cain and Abel but before Seth.

The next step is obvious: Cain married his sister - although Ham allows that it is possible, though unlikely, that Cain could have married a niece.

Let's all pause for a minute and think about the fact that YEC finds multiple generations of incest less disturbing than Genesis being non-literal.

Now, clearly, Ham realizes that he has a problem.  The rest of the chapter is devoted to explaining why various objections to YEC's position of brother-sister marriages are wrong.

Objection 1:  Marrying relatives is wrong in the Bible.

Ham's Reply:  First, he points out we are all relatives since we were all descended from Adam and Eve.  Second, he points out marrying close relatives wasn't denounced by God until the time of Moses.  Third, he pulls Genesis 20:12 to prove that Abraham married his half sister.

Flaws: If laws weren't introduced until the first time they are written in the Bible, why did God get so mad about Cain killing Abel?  The laws about murder don't appear until the time of Moses, either.  Genesis 20 is about Abraham lying to a foreign ruler that Sarah was his sister to save his own skin.  (Actually, it's the second time he prostitutes Sarah out.)  In Genesis 11:27-30, it is clear that Moses is Sarah's uncle.  I concede that marrying an uncle is the same genetic relatedness as marrying a half-sibling; both have ~25% shared DNA markers.  Also, please note that Genesis 11:30 states that Abraham and Sarah had problems reproducing.

Objection 2: We don't allow sibling (or half-sibling) marriages due to increased chances of severe genetic birth defects.  (Note: Ham actually uses the term "deformities" which I find crass.)

Ham's Reply: God created Adam and Eve perfectly. Because Adam sinned, God cursed the world to slowly decay.  Adam and Eve's children could interbreed with each other without problems because the perfect DNA of Adam and Eve hadn't decayed much yet. By the time Moses was born 2,500 years later, enough mutations had accumulated that close relatives couldn't interbreed anymore.  Also, human DNA is getting more and more degenerate over time.

Flaws: First, if Eve is made of Adam's rib, she's a literal clone of Adam.  The problem with that is that two XY genotypes have a 25% chance of having a daughter, a 50% chance of having a son, and a 25% chance of having a completely nonviable YY combination that will not develop due to a missing X chromosome.  That's a pretty high chance of a severe birth defect for the starter parents.  This situation would also lead to a sex ratio of 66% boys and 33% girls in the first generation - which would mess up that whole "be fruitful and multiply" idea.

The Bible may say "Adam and Eve" but the genetics of a literal reading would be "Adam and Steve"......

Secondly, with mutations, it's not the total number of mutations that causes problems - it's the number of shared mutations between the partners.  Let's say that Adam had one really bad recessive gene in his whole genome and that Eve was a XX female without any mutations.

Each of his kids has a 50% chance of inheriting that recessive gene. In YEC world, Adam lived a really long time, so let's say he had 100 children with Eve.  We can safely estimate that 50 of those children carried Adam's recessive gene.

 Assuming that there are ~25 carrier girls and ~25 carrier boys AND that the sibling marriages are roughly random, 25% of the son-daughter marriages of Adam and Eve's kids contain two siblings that  both carry the recessive gene.  Their offspring have a 25% chance of not inheriting the faulty copy, a 50% chance of  inheriting one copy of the gene and a 25% chance of getting both faulty genes and dying.  

The red lines are marriages with a 25% chance per pregnancy of having offspring with a fatal defect.  The yellow lines are marriages that produce healthy children, but have a risk of the same 25% fatality rate appearing in grandchildren.

Plus, another 1/4 of the sibling-sibling marriages contain one partner with the faulty gene where their offspring has a 50% chance of inheriting one faulty copy.  From a population genetics standpoint, those 24 marriages are a time bomb.  The offspring will be fine, but 50% of the kids will carry the gene silently into the next generation.

Assuming for easier math that each type of marriage produces a total of 500 kids:

• "Red" marriages:
• 125 offspring who do not carry the negative gene.
• 250 offspring who are carriers.
• 125 offspring who die before reproducing       

• "Yellow" marriages:
• 500 offspring who do not carry the recessive gene.
• 500 offspring who carry the recessive gene.

• "Green" marriages:
• 250 offspring who do not carry the recessive gene.

Net genotypes of surviving grand kids:

• 750  who carry the recessive gene.
•  875 who do not carry the recessive gene.

If you add different potentially lethal recessive gene for Eve,  25% of their kids have no mutations, 50% have one mutation and 25% have 2 mutations.  For grand children, 33% have no mutations, 39.7% have one mutation, 15% have two mutations and 11.8% died from lethal mutations.

Long story short: ONE recessive mutation in Adam kills off 6.25% of his grandchildren and produces 37.5% of his grand children who have the same mutation.  TWO recessive mutations between Adam and Eve kill of nearly 12% of their grand children and 55% carry one or two recessive mutations.

 By comparison, the Ashkenazi Jewish population percentage of people who carry a single recessive copy of the allele that causes Tay-Sachs disease is 1/25 people or 4%.

Third, remember when I asked you to keep in mind that Sarah and Abraham had problems having children.  Why did Abraham and Sarah have problems having children?  Probably because uncle-niece marriages are also WAY too closely related for genetic safety.

I feel that basic genetics has shot idea down.

And yet:
Ham misses another huge Biblical problem.

When God punishes Cain for killing Abel, he makes him a restless wanderer.  Cain freaks out and says that someone is going to kill him.  God puts a mark on Cain to protect him from being killed.  If the only people on the planet are Adam, Eve, and their offspring, why would Cain need a mark to identify him?  First, he'd have a massive family resemblance.  Second, EVERYONE would know him or of him and remember what happened when Cain killed Abel - so why would they risk being cast out like Brother/Uncle Cain?

Well, the obvious answer is that there were other people around who didn't know Cain......like Cain's wife.  (Thanks to my mom-in-law for pointing this one out; I missed it.)