Due to the advent of science we have been able to fight disease, germs and the such.  We will continue to develop new ways to fight them.  But will it all bite us in the ass some day.  

So theoretically we should be evolving as a species to mutate to fight germs and disease but instead we use science and medicine. So at some point in the future do you thing a germ will come along and kill us all.  One that we could have fought off if we were allowed to evolve to build up an immunity?

This of course would happen thousands or millions of years in the future and we probably will detroy earth by then for other reasons but hypothetically what do you think?