Using physical means of investigation and it does not take us much effort to realize anymore where the physical aspect of our nature comes from through sexual reproduction. But when it comes to the nature of the soul there is no real account in the Bible about the origin of the human soul. While the soul of Adam was clearly created at the time of his physical creation, there is no explicit reference to how the human souls for all of us who are alive today have come from.
Throughout history Christians have held different theories as to when the origin of the human soul took or takes place. There are the Christians who believed that at the beginning of Creation, God created all of the souls of humankind and that they are in heaven waiting for their chance to enter into a human body in order to be created. Origen advanced this theory about the human preexistence; however, this theory has not a biblical foundation nor does it enjoy much of a following today within orthodoxy.
Traducianism theorizes that the human soul is generated along with the physical creation in human reproduction. My guess would be that those who have not really thought about the subject would probably fall into this camp within the Christian community. Traducianism supposes that it is in this way that “in Adam we are all one.” For, if the human soul is passed on through human reproduction then there really is only one human soul in the world, Adam’s, and that we are all manifestations of our first father without invading necessarily into the heresy of universalism. Traducianism, however, could fall into the pitfalls of the heresy of universalism if one is not careful. Traducianists stress that it must be correct because when God rested on the Sabbath all creation is over. This however ignores the obvious Biblical teaching that in Christ we are all new creations in our spiritual reality.
Creationism, the theory that God created the soul of man at the moment of human conception, is the theory which most orthodox circles have embraced. In this view the human soul is independently created by God at the moment of conception. Yet because this view is the majority view it should not be supposed to be the correct view. The Scriptures do not teach explicitly about the origin of the soul and so the Christian should not teach dogmatically about the origin of the soul.