Really, it kind of comes down to semantics.
According to http://www.thefreedictionary.com/Christian, Christianity is defined as:
If you believe in this definition of Christianity, then YES, the Mormons are Christian.1. One who professes belief in Jesus as Christ or follows the religion based on the life and teachings of Jesus.2. One who lives according to the teachings of Jesus.
Mormons worship and believe in Jesus as the Christ, and we try to live our lives based upon the teachings of Jesus.
The reason there is a bit of confusion out there is simply because of the Trinity. Though the word Trinity is never found in the bible, many religions believe that God, his Son, and the Holy Ghost are all part of the Trinity. According to http://christianity.about.com/od/glossary/g/trinitydoctrine.htm the trinity is defined as:
The word "Trinity" comes from the Latin noun "trinitas" meaning "three are one." The Trinity expresses the belief that God is one Being made up of three distinct Persons who exist in co-equal essence and co-eternal communion as the Father, Son and Holy Spirit.The idea of the trinity comes from the scriptures when Christ states that in John 10:30 "I and my Father are one." This has been a confusing point of doctrine for all Christians.
The idea of the Trinity was established during the Nicene Creed, which according to Wikipedia,
The Nicene Creed is the profession of faith or creed that is most widely used in Christian liturgy. It forms the mainstream definition of Christianity for most Christians.In the year 325, (three hundred and 25 years after Christ's birth) there was so much confusion and conflict throughout the different Christian sects that it was decided there needed to be some kind of decision. So a council of men met together and decided to accept the belief that God is one being.
The reason a lot of Christian faiths do not believe that Mormons are Christian, is because of this difference in our beliefs. Members of the Church of Jesus Christ of Latter-Day Saints do not believe in the Nicene Creed or the doctrine of the trinity. We believe that God, his Son Jesus Christ, and the Holy Ghost are three separate beings. We believe that all that confusion in the early Christian church was because the apostles were killed off, and there was no longer a direct communication with God. Men began to decide what they believed and the church became a church of men's philosophies mingled with the teachings of Christ.
We believe this is why there were so many terrible things done by the church in those days. The true church of God couldn't have possibly killed and tortured so many people.
We believe that a restoration of the church of God had to come through God himself. We believe that this was the only way that the perfect doctrine of God could once more be upon the earth. When Joseph Smith had his first vision (read my Mormon Monday about that here), he was visited by God the Father and his Son and saw that they had two distinct separate bodies.
In John 17:11 it says:
The apostles couldn't possibly hope to become a co-equal essence or reach co-eternal communion with God, but they could become one in purpose. Unity is a sign of God's church on earth.
Are Mormons Christian? Yes, I believe we are. However, if your definition of Christian includes faith in the Trinity and a concept of Christ as a vague, formless being, than no. We are not believers in that Christ. We believe in the living being that came to live among the Jews and was resurrected with a body that could be touched by his disciples. We believe in a Christ that is still alive today and expects us to live our lives after his example.
We are followers of Christ, whatever your definition of Him may be. We try to be respectful of other's beliefs and feelings, and to treat them as He would. Even though we may not always agree with other churches on doctrine, we can empathize and share our faith in the redemptive power of our Savior's love. As Christ showed love to all who tried to have faith in him and even to those who didn't, we try to show love to all our brothers and sisters, regardless of who they are, where they live, and what they believe.
That is how become true Christians.