"Genesis 5:4 {The days of Adam after he fathered Seth were 800 years; and he had other sons and daughters.} reveals that Adam and Eve “had sons and daughters” (besides Cain, Abel, and Seth).
We’re only told of Cain/Able - we’re not told of any other children, clearly there were - enough of them, in fact, to create ‘Nod’.
/biblewank
Genesis states that Adam and Eve had another son after Abel and Cain, named Seth, as well as “other sons and daughters.” (Genesis 5:4: “After Seth was born, Adam lived 800 years and had other sons and daughters.”)
Also, I’m now seeing, in the Wikipedia entry for Adam and Eve, that there’s an ancient Jewish text, the Book of Jubilees, which isn’t generally seen as canonical by most Jews or Christians, but which says that Cain’s wife was his sister Awan.
Plus, in Genesis, a lot of the early personalities were said to have lived for many hundreds of years, so if one already believes that, one can also believe that those people had lots and lots of offspring.
We’re also told of a 3rd son Seth.
But the fundamentalist answer is basically incest with an unnamed sister. That’s what I was more or less told by biblical literalists growing up though oddly enough, people weren’t so eager to delve into those implications.
Not according to Ken Ham: see @crowmanyclouds’s link.
In small populations where do you think mates would come from? Even from the evolutionary model, close relatives were necessary until a sufficient population existed. The “fundamentalist” understanding is that with genes only one generation removed from perfect, the issue we would see today would not have been as big a problem. It has nothing to do with not being “eager to delve into those implications.”
If the choices are “breed with very close relatives and have a higher risk of genetic problems” and “breed with nobody and guarantee that you’ll die out”, the solution seems pretty simple. It might be very icky but it’s no different than starving and having to eat bugs or worms or resort to cannibalism.
Wouldn’t they breed with the population they came from? So the first homo erectus would have bred with a Cro Mangnon from its tribe. The new genes would have to be dominant to proceed. Eventually all of the tribal children would have those new genes. Then they would eventually isolate from the original population and lose the ability to breed with them.
Basically, the plot of Clan of the Cave Bear.
FWIW, Homo erectus predated Cro-Magnon by a lot
An excellent point, Sir. Live long, and prosper.
Well, they were very paitent. Women like that.
Sure, but the Pit can also sometimes be more about mockery and poking fun than an angry rant. With all we have to rant about these days, I hthink we sometimes forget this.
For what it’s worth, the idea that a Vulcan and a human could interbreed is scientifically ridiculous.
One of the Treks explained that by giving every sentient species a common ancestor.
As Larry Niven put it so memorably in his essay Man of Steel, Woman of Kleenex, “Superman would find it as easy to mate with an ear of corn as with LL” (He used initials to avoid specifiying Lois Lane, Lana Lang, Lori Lemaris, or any other candidate)
Jesus became human to save humans from being fallen creatures due to Original Sin (commited by our human forebears), that’s why he Vulcans can’t be saved by “human Jesus”. That’s not fundamentalism or even literalism, it’s like the whole point of Christianity. (Of course thios doesn’t mean that Jesus, Heaven or Salvation are true, it’s just what most Christians believe).
There is nothing in the Bible about aliens (in the SciFi meaning) so almost anything else is just speculation but Vulcans can’t be saved in the same way that even the smartest chimpanzee can’t be saved.
But, this also does not mean that Vulcans go to hell. I don’t know what happens to them but just being Vulcan would not condemn you.
There are many theories about whether aliens can be saved, including one in which Christ was born, died, and resurrected on every planet with intelligent species.
Lex Luthor? 
So he’s saying because the Bible mentions nothing other than the cretion of Earth and Man, and the Jesus of the Bible is THE one and only Savior and his sacrifice for Man THE one and only sacrifice, then there can be nobody else anywhere to save AND therefore there can be nobody else anywwhere. Because or else the Bible would mention it, I suppose.
Indeed.
Myself insofar as salvation and beings from other worlds I have a Bradburyist leaning; each world would have its Savior(s), if they need to.
They end up in limbo with the un-baptized babies.