Why is Evolution at odds with Christianity?

It's because human origins through evolution questions the origins of human nature. The troublesome parts of human nature - sin - supposedly came through and act of rebellion against God by the original and fully responsible human beings. Jesus death on the cross attoned for that according to accepted Christian theology. What if human nature, including it's problem areas, are products of evolution...then what did Jesus die for? That is the troubling question Christians ultimately are called to address when they consider human origins through a gradual evolutionary process. See my website http://www.evolutionaryspirituality.com and my book Stepping Through the Narrow Gate.