Jesus could not have been human because he is God's son and God was not human.The Bible tells us that Jesus is co-eternal with God (this means that like God Jesus exists forever) he became a human so he could enter the world and died to save humans.
Jesus took a human body to save our bodies and he took a human mind to save our minds. Without becoming a man in his emotions he couldn't save ours. He became man in full so that he could save us in full.