I did not write the post above. Someone is impersonating me.
To address the issue: God created Adam first. He saw that it was not
good for the man to be alone so He put Adam to sleep and created Eve
out of his side. All of the genetic code used for our bodies had no
flaw at this point, no deviation from being perfect and true to God's
creation and design.
Marriage between people was not prohibited between people until the
time of Moses, because it was only then that mistakes began to enter
in that would cause deformities and life-threatening diseases. As
such, God instituted the barrier of not marrying close relatives to
prevent those diseases.
You can see a very informative video about this process here (begins
at 15:55):
One Race, One Blood
https://www.youtube.com/watch?v=KbODW6XO8zY&t=15m55s
--
Rick C. Hodgin