Philipp Messer, 3CPG faculty member, spoke July 14th 2016 at the Allied Genetics Conference about the fatal flaw of CRISPR/Cas9 gene drives: eventually, they will stop working. He argues that this inevitable eventual breakdown is a good thing because it could be manipulated to to keep gene drives in check and help to prevent unintended harm. 

Science News article: https://www.sciencenews.org/article/seeing-upside-gene-drives-fatal-flaw