I asked a Christian doctor friend of mine about his religion and his profession. He explained that being a doctor is very much like being a car mechanic. He learnt about different parts of the body and how to fix them when they go wrong.
However, unlike a car mechanic, he does not have the complete blueprint plan of how the body was made and how it functions. He explained that, thankfully, the Creator decided to keep some parts of the blueprint secret in case we humans ruin the final product completely.