A: Yes, students of The Urantia Book do recognize that Jesus was the Son of God as well as being the Son of Man. Which of these two qualifications is more meaningful? Each of us is a son of God--that was one of Jesus' primary teachings, the value of the individual, and that while God is no respecter of persons, we're each equally important to our Father in heaven. Christianity tends to emphasize the teaching that Jesus was a Son of God, neglecting the equally valuable realization that Jesus was also a Son of Man and neglecting to emphasize that we too are sons of God, not in the same sense that Jesus was but in a sense that is equally as cherished and loved by God the father.
By Jesus taking on the role of Son of Man he acknowledged that he would live a life in the flesh just as we mortals do. Although having a pre-existent divine existence before becoming a mortal, he accepted status as a mortal of the realm, was subject to the same vicissitudes of life that mortals are subject to, lived life as we do. Jesus was human as well as divine.
Students of The Urantia Book do not believe that Jesus died on the cross to save us from our sins; we do not accept the Christian atonement dogma that proposes that God required a human/divine sacrifice in order to be appeased. We hold the Father in heaven in much higher regard than such a primitive anthropomorphized opinion casts. As the Son of Man, Jesus submitted to torture and a barbaric death, not because God willed it but as a way of making the continuity of life after death undeniable.
Not only did he teach that death was not the end of existence, that in his Father's house are many mansions where he has prepared a place for us, but he manifested this teaching by returning from death. This, and not that he died for sins, is the great gift Jesus has given to humanity for all time that has been lost to much of Christian theology.
You concluded by saying "If not, then this is not Christianity." Exactly. The Urantia Book is a new revelation of truth, not an amplification of Christianity nor of any other religion on earth. The Urantia Book does not claim to be Christian; it does claim to be Jesusonian — to be an accurate restatement of Jesus' life and teachings devoid of religious dogma."