Kate, I been thinking about this question (mainly during the meeting this morning). Isn't the problem simply that because we don't understand a chemical, biological or physical process that we tag it as supernatural? If we take that to its logical conclusion we end up falling to our knees at the sight of a plane in the sky and doing obeisance.
For me it boils down to a question of faith. Those with faith in religion simply ascribe anything they don't understand to a creator. The scientific approach though is to build on the body of knowledge, hard won by experimentation, testing of hypotheses and observation. The results open to debate and critisism by peers. Those with “faith" in science are content to admit that they just don’t yet know. They have confidence though that due to the cumulative build up of knowledge over time that one day, someone will. I suppose that is a form of faith but it is based on a mountain of unassailable knowledge.
I can’t claim to have undertaken the amount of reading that Cofty has done but all that I have read and investigated leads me inexorably to the conclusion that natural selection is a wonderful engineer. The sort of awe that inspires creationists just leads those with enquiring minds to ask “why”? Eventually the answers emerge. It is not impossible that some unknown force has instigated and guided things but to consider this as a creator or suitable for our worship ignores the completely amoral nature of life and natural phenomena.
By the way, I have followed your life turmoil and wish you nothing but the best with your family circumsatnces and private life. SF