Mark mentions the Holy Spirit in the Baptism. This is the only time that he refers to it and this might suggest that he believed in the Trinity. If he believed in the Trinity then he certainly believed that Jesus was literally the Son of God. Mark certainly brings together the ideas of God the Father, Jesus the Son of God and the Holy Spirit in the story of Jesus’ Baptism.
Son of God can be interpreted in three different ways. It can mean the king; in many ancient Mediterranean societies, kings were thought to be descended from Gods E.g. Pharaohs, Romulus and Remus and Greek heroes. Secondly all Jews were Sons of God because they are “beloved of God”. Finally it can literally mean God’s son which means that only Jesus is the Son of God.
Fundamentalists literally believe Jesus is the Son of God and therefore he is God, the second person in the Trinity. They have a literal interpretation of everything Jesus said in the bible, therefore it affects the way they live their lives. If they believe Jesus is God they will pray to him as God and worship him as God. Fundamentalists believe that Jesus’ teaching is always right and non-negotiable because Jesus’ word is God’s word and God is never wrong. On divorce for instance Jesus says: “No human being must separate what God has joined together” (Mark 10:9) The vast majority of people nowadays believe that divorce is acceptable if the couple are unhappy. Fundamentalists, however, believe that divorce is never acceptable under any circumstances because Jesus said so and he is always right.
Liberals believe that Jesus is the Son of God by adoption and not God’s actual biological son, though they do see him as special. They pray only to God though they do pray to God through Jesus. However, they never pray to Jesus as God. Liberals believe Jesus was just a first century human being so his word and his teachings don’t carry the same eternal truth as God’s word carries. His teaching can in some areas be seen as irrelevant in today’s society because he didn’t know how society would have progressed 2000 years from his time. They see all the bible writers as culturally conditioned. They taught morals and ideas which worked in their culture but don’t necessarily work in ours.
Conservatives are on the side of the Liberals on some issues and the side of the Fundamentalists on others. On the issue of Son of God they are more or less on the same side as the Fundamentalists. They are also similar to Fundamentalists on Jesus’ teaching even when it doesn’t agree with society today.
The vast majority of Jesus’ teaching is on social issues such as poverty and race. This doesn’t divide Christianity. It is the moral teaching such as divorce and homosexuality where Liberals, Fundamentalist and Conservatives each have their own ideas. The moral teaching is only a very small portion of the New Testament, the majority of Jesus’ teaching was social which Fundamentalists, Liberals and Conservatives all accept and agree on and follow Jesus’ example in.
The problem with the title Son of God is that the New Testament is not clear on what it actually means. Because it is left unclear and open to different interpretations, knowing which one to believe can be a very difficult task. It is generally agreed that Mark’s Gospel is not clear on the title but it doesn’t offer dozens of different interpretations. It only has two possible meanings, either, Jesus is God (part of the Holy Trinity,) or Jesus is not God (but is God’s son by adoption).
This ambiguity is unfortunate for Christianity worldwide because fundamentalists, liberals and conservatives all have different ideas and this leads to conflicts within the religion. Some argue that the differing interpretations of what Son of God means can be seen as confusing to people already in the Church and can be off-putting to people thinking of joining. . They believe it creates disunity in the Church which is not good and is seen as a weakness in the religion. Those who argue that the ambiguity is not a problem defend the standpoint that it is an open issue and people should be allowed their own views. Faith is not an exact truth and debate can help people cement their beliefs.
I would say that it is important to retain the title because this alone does not deter people from becoming Christians. Christians usually want to join the Church because of what they believe in, not because the faith is undecided on one issue. If the title were scrapped, this would mean changing something that has been in existence for around 2000 years and has been so central to Christianity for so long. Changing a historical religion now is far more likely to put people off than disagreement over what a title means.
Therefore, I think there is absolutely no case for dropping it. Dispensing with the title of Son of God would cause more trouble than it saved.