I don't know what monogenes meant to a Greek speaker 2000 years ago and I don't think anybody else does either. I looked it up online and got this from the New Testament Greek Lexicon. I also saw that Plato used it in pretty much the same manner as defined below.
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- single of its kind, only
- used of only sons or daughters (viewed in relation to their parents)
- used of Christ, denotes the only begotten son of God
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That definition of monogenes is a lot better than "one and only son". Let's see if we come to an agreement on this NIV error then we can move on to factual errors in the KJV.