So do all Christians, in a sense. They believe that Jesus was either Satan's son or brother, depending on whether or not they believe God the Father and Jesus Christ are the same person. 
 
Colossians 1:16 reads, "For by him [Jesus] were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him:" 
 
The bible states that Lucifer fell from heaven: 
 
Isaiah 14:12 reads, "How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!" 
 
If Jesus Christ made the heavens and the earth and everything in them, then Christian churches must believe that Jesus Christ created Satan. The word "father" means "creator". So, the Christian world, if they believe in the bible, must believe Jesus is Satan's father. 
 
We "Mormons", however, believe that God the Father and Jesus Christ are not the same person and that Jesus Christ created the heavens and the earth under the direction of the Father. This is evident here: 
 
Hebrews 1:1-2 "1 God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets, 
2 Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;" 
 
We believe that God the Father is the father and creator of all of us, and this includes Jesus and Satan. This makes Jesus and Satan our brothers. 
 
Jesus said to Mary in John 20:17, "Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God." 
 
If God is everyone's father, then why not Satan's father, too? Did Satan create himself? Is it because God would not create such a wicked person? Does this mean that Hitler and others like him created themselves, too?