How does one reconcile the idea that physical disability is the result of sin with Exodus 4:11? I believe that disability is a result of Adam and Chavva's sin.

Here's the logic behind my reasoning.


Adam and Chavva were not disabled according to scripture.
Adam and Chavva committed sin.
Disability occurred after their sin.
Therefore, disability was a result of the introduction of sin.


How does one reconcile the belief that disability is a result of sin, and sin affecting the world, with the following scripture (Exo. 4:11):


  And YHVH said to him, "Who made man's mouth? Or who makes the dumb, or deaf, or the seeing, or the blind? Have not I, YHVH?"
In the post that you are referring to, it is possible that when the person says "disability is the sad result of sin in the world" they are referring to the perfect vs. post-perfect world in Genesis with Adam and Eve. God created Adam and Eve in His own image ( Genesis 1:27) and after the fall death entered the world through sin (Romans 5:12); therefore, physical disability must have come from sin eventually because sin entered through us all from Adam and Eve. 

However, this might not be of what they were referring when they said "disability is the sad result of sin in the world." I do not think that disability is a direct result of your sin or the inherited sin of your fathers NECESSARILY. I will conclude with two points. 

1 God does what He wants.


  For I know that the Lord is great,
      and that our Lord is above all gods.
  6 Whatever the Lord pleases, he does,
      in heaven and on earth,
      in the seas and all deeps.
  7 He it is who makes the clouds rise at the end of the earth,
      who makes lightnings for the rain
      and brings forth the wind from his storehouses. - Psalm 135:5-7


2 God is smarter than we are. 


  For my thoughts are not your thoughts,
      neither are your ways my ways, declares the Lord.
  9 For as the heavens are higher than the earth,
      so are my ways higher than your ways
      and my thoughts than your thoughts. - Isiah 55:8-9


That's why disability exists, plain and simple. Because God said it does. Because sometimes it brings Him Glory even if we can't see it.