You assume that God is responsible for childhood leukemia and mosquitoes? Why would you make that assumption? Do you have a picture of some big ogre in the sky pointing to a hapless child and bestowing blood cancer? Good grief...no wonder you are an unbeliever!
I believe you believe your omni everything god created heaven and earth. That includes all that exists. You cannot cherry pick the good bits of nature and blame the bad on someone else, that implies that omni is a misrepresentation.