Those weren't the only offspring Adam and Eve had, and people lived hundreds of years back then. Obviously, some brothres and sisters were married
together back then, but the problem with bilogical deformities was not an issue as they were at the prototype end of the human race and genes had not
been damaged as they have become through the centuries.
The Bible does not say Cain found a wife in the land of Nod, but that he "knew" his wife - they had sex - and she bore a child. Cain left to Nod
with his wife, a relative.
Adam lived to be over 900 years old, and he and Eve had plenty of children, and the children had children, and so on.



Is it pink? With a blue bow on its tail? I promise I'll get you
something. Lets see, a pony is a farm animal... a cow! Perfect, you can ride it, then when it dies, you can have steak for next few
weeks.