Just wanted to chime in here with a book suggestion : "The Problem if Pain" by C.S. Lewis.

Tackles this problem from a christian apologista perspective. Its about as intellectual an analysis as you are going to get on this subject matter. I personally don't agree with 100% of it, but Lewis always presents arguments I never would have considered otherwise. Worth a read.

Also, listening to scientists and engineers discuss issues of morality (e.g. this comments section) is always a painful experience. The analytical mind is not often applied appropriately to matters of philosophy. At least thats my impression.