I looked into this a little bit for my own personal curiosity. You are right that AIG does not teach this, though they acknowledge it as a view some creationists hold. Their reason for rejecting it is because hypothetically a cloned human created from two females would have to have a sin nature. I love AIG arguments.
However, the idea that a sin nature is passed on biologically through the father is found all over in popular level Christian theology explanations, as a quick google search will show. So the idea that McKnight just concocted a straw man and intentionally misrepresented creationist beliefs to make something he disagreed with look bad doesn't hold water.
An apologetics ministry here:
Genesis and Genetics