They do not believe in the dual nature of Jesus, being both fully God and fully man. Jesus was God became man, died and became God again. Christ is now fully God, but subordinate to his Father. Jesus is Jehovah of the Old Testament.
AND now Abinadi said unto them: I would that ye should understand that God himself shall come down among the children of men, and shall redeem his people. And because he dwelleth in flesh he shall be called the Son of God, and having subjected the flesh to the will of the Father, being the Father and the Son—The Father, because he was conceived by the power of God; and the Son, because of the flesh; thus becoming the Father and Son—And they are one God, yea, the very Eternal Father of heaven and of earth. (Mosiah 15:1-4)
Wherefore, the Almighty God gave his Only Begotten Son, as it is written in those scriptures which have been given of him. He suffered temptations but gave no heed unto them. He was crucified, died, and rose again the third day; And ascended into heaven, to sit down on the right hand of the Father, to reign with almighty power according to the will of the Father; That as many as would believe and be baptized in his holy name, and endure in faith to the end, should be saved—Not only those who believed after he came in the meridian of time, in the flesh, but all those from the beginning, even as many as were before he came, who believed in the words of the holy prophets, who spake as they were inspired by the gift of the Holy Ghost, who truly testified of him in all things, should have eternal life, As well as those who should come after, who should believe in the gifts and callings of God by the Holy Ghost, which beareth record of the Father and of the Son; Which Father, Son, and Holy Ghost are one God, infinite and eternal, without end. Amen. (D&C 20:21-28)
Born of a Virgin
LDS believe Jesus was born of a virgin. Mary was in some unspecified manner made pregnant by God the Father, through the power of the Holy Spirit. Hence Jesus is not a metaphorical Son, but a begotten Son. Jesus is not the son of the Holy Spirit, but of the Father through the Holy Spirit.
And behold, he shall be born of Mary, at Jerusalem which is the land of our forefathers, she being a virgin, a precious and chosen vessel, who shall be overshadowed and conceive by the power of the Holy Ghost, and bring forth a son, yea, even the Son of God. (Alma 7:10)