Adam's status after the fall was:
1. He was banished from the presence of God and partook of the spiritual death. Now that was a terrible calamity. At least, as we read in the 9th chapter of 2nd Nephi, it would have been a most terrible thing, that banishment from the presence of God, if there had been no remedy.
2. He also partook of the temporal or physical death, and that would have been also a terrible calamity if there had been no remedy for it.
3. He gained knowledge and experience--knowledge of good and evil.
4. He obtained the great gift of posterity.
Because of Adam's transgression, a spiritual death--banishment from the presence of the Lord--as well as the temporal death, were pronounced upon him. The spiritual death came at the time of the fall and banishment; and the seeds of the temporal death were also sown at that same time; that is, a physical change came over Adam and Eve, who became mortal, and were thus subject to the ills of the flesh which resulted in their gradual decline to old age and finally the separation of the spirit from the body. (Doctrines of Salvation 3 Vols. Ed. Bruce R. McConkie [1954-56], 1:111-112)
There are, in fact, five things that came into being and continue to exist because of the fall. None of these things would have existed if there had been no fall, and all of them are essential parts of the divine plan of salvation. They are:
1. Temporal death. This is the natural death; it occurs when body and spirit separate; it results in corruption and decay. Because of the atonement of Christ all men will be raised from corruption to incorruption, from mortality to immortality, thence to live everlastingly in a resurrected state.
2. Spiritual death. This is death as pertaining to the things of the Spirit. It is death as pertaining to things of righteousness. It is to be cast out of the presence of the Lord. It is a way of life which is in opposition to that of the Father of us all. Because of the atonement, because the Lord Jesus bore our sins on conditions of repentance, we have power to gain eternal life, which is spiritual life, which is a life of righteousness, which is life in the presence of our God.
3. Mortality. Mortal life comes because of the fall. If there had been no fall, there would be no mortal life of any sort on earth. Mortal life is life where there is death. Death must enter the world to bring mortality into being.
4. Procreation. Before the fall there was no procreation. I repeat, for thus saith the Holy Word, before the fall there was no procreation. Adam and Eve, in their Edenic state, could not have children, nor, as we shall see, could any form of life when first placed on the newly created paradisiacal earth.
5. A probationary estate. We are here to be tried and tested, to see if we will believe the truths of salvation and keep the commandments while we walk by faith. After the fall men became carnal, sensual, and devilish by nature, and the plan of salvation calls upon them to put off these worldly snares and to put on Christ. ("The Three Pillars of Eternity," BYU Devotional, 17 February 1981)
The fall of Adam brought temporal and spiritual death into the world. Temporal death is the natural death; it occurs when body and spirit separate, thus leaving the body to return to the dust whence it came. Spiritual death is to be cast out of the presence of the Lord and to die as pertaining to the things of righteousness. Adam died spiritually when he was cast out of the heavenly presence found in the garden, and he remained spiritually dead until he repented and was born again through baptism and the receipt of the Holy Spirit. Having thus the companionship of the Holy Ghost, he became alive in Christ and was again guided and directed from on high. He was again in the presence of the Lord. Adam died temporally when his spirit separated from his mortal body. (A New Witness for the Articles of Faith , pp.86-87)
To bring the plan of happiness to fruition, God issued to Adam and Eve the first commandment ever given to mankind. It was a commandment to beget children. A law was explained to them. Should they eat from "the tree of the knowledge of good and evil" (Genesis 2:17), their bodies would change; mortality and eventual death would come upon them. But partaking of that fruit was prerequisite to their parenthood.
While I do not fully understand all the biochemistry involved, I do know that their physical bodies did change; blood began to circulate in their bodies. Adam and Eve thereby became mortal. Happily for us, they could also beget children and fulfill the purposes for which the world was created. Happily for them, "the Lord said unto Adam [and Eve]: Behold I have forgiven thee thy transgression in the Garden of Eden" (Moses 6:53). We and all mankind are forever blessed because of Eve's great courage and wisdom. By partaking of the fruit first, she did what needed to be done. Adam was wise enough to do likewise. Accordingly, we could speak of the fall of Adam in terms of a mortal creation, because "Adam fell that men might be" (2 Nephi 2:25).27
Other blessings came to us through the Fall. It activated two closely coupled additional gifts from God, nearly as precious as life itself--agency and accountability. We became "free to choose liberty and eternal life . . . or to choose captivity and death" (2 Nephi 2:27). Freedom of choice cannot be exercised without accountability for choices made. (Ensign, Nov. 1993, p. 34)