Alma Allred argues that Brigham used "Adam" as a title to refer to both God the Father and Adam.
Alma Allred, "The So-called Adam-God Theory" (1989)
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The solution to the Adam-God controversy is summed up in the fact that one of God’s names is Adam. The name Adam is a Hebrew term meaning Man or Mankind—hence the designation in the writings of Moses, “Man of Holiness is his name.”
The terms Man and Adam are interchangeable. Footnote a in Genesis 5:1 says, “In Hebrew adam is also a common noun, meaning man, or mankind.”
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There are two or three quotations of President Young where the Adam Sr./ Adam Jr. explanation does not fit well. There are many more where it does. In the instances where the quotation is opposed to scriptural doctrine, we may conclude that the recorders wrote what they thought they heard Brigham Young say rather than what he actually said. The controversy engendered by President Young’s comments could have been quickly and succinctly handled by him while he was alive. It appears though that he was not interested in clearing up the problem; rather, it appears that he preferred to let the Lord reveal the answer to those who would inquire.