(Originally posted in the Religious section of Perspectives in response to a Islamic thread on Adam).
This thread is mainly for those who literally believe that God created Adam as recorded in Genesis and elaborated on in the Quran.
The first reason why I don't believe in Adam (the one written about in the Bible and the Quran) is because I believe the origins of that story did not come from revelation to Moses or Muhammed, but from the "heathen" Sumerians. The authors of the Bible stoled and slightly changed the story; then Muhammed came along and added a few elements to the story as well. The following wikipedia article is sufficient for my needs and it contains references to more scholarly resources (pay special attention to the section on Mythological Connections): http://en.wikipedia.org/wiki/Adam_and_Eve
The apologist will say, well that doesn't prove that the story of Adam is made up, it just shows that it is a very old story. Perhaps Adam really did exist and his story was passed down from generation to generation being corrupted as it went and then Moses claim along and restored the true account of what happened.
In response, I now turn to two different strands of scientific research that completely support each other and discredit the Adam story. The first is DNA evidence. Population DNA is a field that unfortunately is not understood well by the general public. I would like you all to be able to understand the basics of this field. In short, most of our chromosomes were made by shuffling the genes we got from our mother and father. It can be quite difficult to tell which genes came from which parent unless we know a lot about the genetic makeup of both sides of the family.
However, males have a complete Y-chromosome that they got virtually unchanged from their fathers generation after generation. Now occasionally, a DNA sequence in the Y chromosome will develop a mutation and that mutation will be passed on to all of that individual's male descendents. But, that mutation will not be found in all of the other males in a population. New mutations will occur and be present in different ancestral lines. Now, in addition to these mutations occuring, people migrate, so you end up with clusters of people in different parts of the world with high percentages on specific mutations. Since we know the approximate rate of mutations occuring, we can calculate approximately when a mutation occured and how closely diffirent peoples are related.
In addition, all of us have mitochondrial organelles in our cells that act as power generators for the work the cells do. We all got our mitochodrial DNA virtually unaltered from our mothers. mt-DNA also mutates but at a much slower rate. We know what mutations are present around the world today, and working backwards, we are able to identify our genetic "Adam" and our genetic "Eve".
Now, many Christians believe Adam lived 6,000 years ago. They figured this out by adding up the ages of each link in the extensive genealogies given in the Bible. But, we have been able to calculate that the common male ancestor of every living male lived some 60,000 years ago in sub-Saharan Africa, which means that all humans lived in Africa at least until that time. Unlike his Biblical namesake, this Adam was not the only man alive in this era. Rather, he is unique because he was the only one to have his descendents survive to the present day. It is important to note that Adam does not literally represent the first human. He is the coalescence point of all genetic diversity found in the world's disparate peoples. Adam had human ancestors as well, but we have no genetic evidence of them. To learn more about National Geographic's Genographic project view their online exhibit (https://www3.nationalgeographic.com/genographic/atlas.html )
Genetic Eve never knew Genetic Adam. She lived 143,000 years ago. (http://news.bbc.co.uk/1/hi/sci/tech/999030.stm )
The third reason, I don't believe the Genesis account of the origin of man is due to the fossil record and what it reveals about human evolution. To save space, and because I am sure many of you are familiar with this, I will just post a link (select launch documentary): http://www.becominghuman.org/
It is interesting to me how both the DNA present in our cells and the fossil record (and the archaeological evidence) testify of the same story for the origin of mans and it is nothing like that recorded in Genesis. We really did come from apes. The fact that that sounds odd is no rebuttal to all of the evidence scientists have gathered. And nothing the Bible or Quran has to say can be taken as an authoritative rebuttal because it is the authority of these holy books that are presently in question.