God the Father is married and there is a Mother God (Answers to Gospel Questions, Joseph Fielding Smith, Vol. 3, pp. 143-144)
All men and women who have ever lived on Earth are the spirit offspring of Heavenly Father and Heavenly Mother. Every person was conceived and born in a pre-existent spiritual realm (Mormon Doctrine, p. 589)
Black people are black because of their misdeeds in the pre-existence (Three Degrees of Glory, LDS Apostle Melvin J. Ballard, p. 21)
“You see some classes of the human family that are black, uncouth, uncomely, disagreeable and low in their habits, wild, and seemingly deprived of nearly all the blessings of the intelligence that is generally bestowed upon mankind….Cain slew his brother. Cain might have been killed, and that would have put a termination to that line of human beings. This was not to be, and the Lord put a mark upon him, which is the flat nose and black skin.” (Brigham Young, Journal of Discourses, vol. 7, p. 290).
“Shall I tell you the law of God in regard to the African race? If the white man who belongs to the chosen seed mixes his blood with the seed of Cain, the penalty, under the law of God, is death on the spot. This will always be so.” (Brigham Young, Journal of Discourses, vol. 10, p. 110).