Lowry Nelson references the premortal life as one of the reasons for the priesthood ban.
Lowry Nelson, Letter to George Albert Smith, June 26, 1947, Utah State University Merrill-Cazier Special Collections
Dear President Smith:
I am in receipt today of a letter from President Heber Meeks, an old school friend, copy of which I am enclosing together with a copy of my reply. It is self-explanatory. Perhaps I am out of order, so to speak, in expressing myself as I have. I have done so out of strong conviction on the subject, and with the added impression that there is no irrevocable church doctrine on this subject. I am not unaware of statements and impressions which have been passed down, but I had never been brought face to face with the possibility that the doctrine was finally crystallized. I devoutly hope that such crystallization has not taken place. The many good friends of mixed blood - through no fault of theirs incidentally - which I have in the Caribbean and who know me to be a Mormon would be shocked indeed if I were to tell them my Church relegated them to an inferior status. As I told Heber, there is no doubt in my mind that our Church could perform a great service in Cuba, particularly in the rural areas, but it would be far better that we not go in at all, than to go in and promote racial distinction. I wanted you to know my feelings on this question and trust you will understand the spirit in which I say these things. I want to see us promote love and harmony among peoples of the earth.
Sincerely,
Lowry Nelson
(signed)