[Joseph Fielding Smith]
Why did Adam come here? Not subject to death when he was placed upon the earth, there had to come a change in his body through the partaking of this element---whatever you want to call it, fruit---that brought blood into his body; and blood became the life of the body instead of spirit. And blood has in it the seeds of death, some mortal element. Mortality was created through the eating of the forbidden fruit, if you want to call it forbidden, but I think the Lord has made it clear that it was not forbidden. He merely said to Adam, if you want to stay here this is the situation. If so, don't eat it.
[Address given at LDS Institute of Religion; Joseph Fielding Smith; Salt Lake City, Utah; January 14, 1961, in Quotations Dealing with the Relationship of Our First Earthly Parents to Our Heavenly Parents (1830-1978)]