Question: What is the Adam-God Theory?

Brigham Young taught that Adam, the first man, was God the Father

Brigham Young taught that Adam, the first man, was God the Father. Since this teaching runs counter to the story told in Genesis and commonly accepted by Christians, critics accuse Brigham of being a false prophet. Also, because modern Latter-day Saints do not believe Brigham's "Adam-God" teachings, critics accuse Mormons of either changing their teachings or rejecting teachings of prophets they find uncomfortable or unsupportable.

Brigham never developed the teaching into something that could be reconciled with LDS scripture and presented as official doctrine

Brigham Young appears to have believed and taught Adam-God, but he never developed the teaching into something that could be reconciled with LDS scripture and presented as official doctrine. Therefore, we simply don't know what Brigham Young meant, and modern leaders have warned us about accepting traditional explanations of Adam-God. Since the Church has rejected it, we won't be able to answer the question until the Lord sees fit to reveal more about it.

The Church's official position is that Adam-God is not the doctrine of the Church

Regardless of which approach the reader prefers to accept, the Church's official position on Adam-God is clear: as popularly understood, Adam-God (i.e., "Adam, the first man, was identical with Elohim/God the Father") is not the doctrine of the Church. If there are any particles of truth to anything surrounding the Adam-God doctrine, one would expect those things to harmonize with what has already been revealed. Only further revelation from the Lord's anointed would be able to clear up many points surrounding that doctrine.

Notes

Question: What is the Adam-God Theory?