Biotech has been betting big on Crispr, the gene-editing technique that promises to snip away some of humanity\u2019s worst diseases. But last May, a small case study suggested the much-hyped technology might actually be quite dangerous\u2014and pop went the Crispr bubble, briefly tanking shares of Crispr companies like Editas Medicine, Intellia Therapeutics, and Crispr Therapeutics.