Most Mormons are unaware of the fact that early LDS leaders taught that God the Father was actually married to Mary, Jesus' mother. Brigham Young, second President, and Prophet of the LDS Church stated:
This matter was a little changed in the case of the Savior of the world, the Son of the living God. The man Joseph, the husband of Mary, did not, that we know of, have more than one wife, but Mary the wife of Joseph had another husband. On this account infidels have called the Savior a bastard. This is merely a human opinion upon one of the inscrutable doings of the Almighty. That very babe that was cradled in the manger, was begotten, not by Joseph, the husband of Mary, but by another Being. Do you inquire by whom? He was begotten by God our heavenly, father (Journal of Discourses, 11:268; emphasis added)
LDS Apostle and General Authority, Orson Pratt explains clearly:
but it was the personage of the Father who begat the body of Jesus; and for this reason Jesus is called the Only Begotten of the Father; that is, the only one in this world whose fleshly body was begotten by the Father. There were millions of sons and daughters whom He begat before the foundation of the world, but they were spirits, and not bodies of flesh and bones; whereas, both the spirit and body of Jesus were begotten by the Father the spirit having been begotten in heaven many ages before the tabernacle was begotten upon the earth. The fleshly body of Jesus required a Mother as well as a Father.
Therefore, the Father and Mother of Jesus, according to the flesh, must have been associated together in the capacity of Husband and Wife; hence the Virgin Mary must have been, for the time being, the lawful wife of God the Father: we use the term lawful Wife, because it would be blasphemous in the highest degree to say that He overshadowed her or begat the Saviour unlawfully. It would have been unlawful for any man to have interfered with Mary, who was already espoused to Joseph; for such a heinous crime would have subjected both the guilty parties to death, according to the law of Moses. But God having created all men and women, had the most perfect right to do with His own creation, according to His holy will and pleasure; He had a lawful right to overshadow the Virgin Mary in the capacity of a husband, and beget a Son, although she was espoused to another; for the law which He gave to govern men and women was not intended to govern Himself; or to prescribe rules for his own conduct.
It was also lawful in Him, after having thus dealt with Mary, to give Mary to Joseph her espoused husband. Whether God the Father gave Mary to Joseph for time only, or for time and eternity, we are not informed. Inasmuch as God was the first husband to her, it may be that He only gave her to be the wife of Joseph while in this mortal state, and that He intended after the resurrection to again take her as one of his own wives to raise up immortal spirits in eternity (Orson Pratt, The Seer, 158; emphasis added).
Orson Pratt agrees with Young when he says, "the Father and Mother of Jesus, according to the flesh, must have been associated together in the capacity of Husband and Wife; hence the Virgin Mary must have been, for the time being, the lawful wife of God the Father. Keep in mind Pratt was a Mormon Apostle he was a General Authority of the LDS Church.