Thus you may continue and trace the human family back to Adam and Eve, and ask, are we of the same species with Adam and Eve? Yes, every person acknowledges this; this comes within the scope of our understanding.
But when we arrive at that point, a vail (sp. veil) is dropped, and our knowledge is cut off. Were it not so, you could trace back your history to the Father of our spirits in the eternal world. He is a being of the same species as ourselves; He lives as we do, except the difference that we are earthly, and He is heavenly. He has been earthly, and is of precisely the same species of being that we are. Whether Adam is the personage that we should consider our heavenly Father, or not, is considerable of a mystery to a good many. I do not care for one moment how that is; it is no matter whether we are to consider Him our God, or whether His Father, or His Grandfather, for in either case we are of one species---of one family---and Jesus Christ is also of our species. *** Now to the facts in the case; all the difference between Jesus Christ and any other man that ever lived on the earth, from the days of Adam until now, is simply this, the Father, after He had once been in the flesh, and lived as we live, obtained His exaltation... It is all here in the Bible; I am not telling you a word but what is contained in that book.
Things were first created spiritually; the Father actually begat the spirits, and they were brought forth and lived with Him. Then He commenced the work of creating earthly tabernacles, precisely as He had been created in this flesh himself, by partaking of the course material that was organized and composed this earth, until His system was charged with it, consequently the tabernacles of His children were organized from the course materials of this earth.
When the time came that His first-born, the Saviour, should come into the world and take a tabernacle, the Father came Himself and favoured that spirit with a tabernacle instead of letting any other man do it. The Saviour was begotten by the Father of His spirit, by the same Being who is the Father of our spirits, and that is all the organic difference between Jesus Christ and you and me. And a difference there is between our Father and us consists in that He has gained His exaltation, and has obtained eternal lives.
[Source: J. D. 4:217-219; Discourse by President Brigham Young delivered in the Tabernacle, Salt Lake City; February 8, 1857, in Quotations Dealing with the Relationship of Our First Earthly Parents to Our Heavenly Parents (1830-1978)]