Genetic modification just became fast, easy and cheap, thanks to CRISPR technology which allows you to take out bad genes out of DNA — like for diseases — and insert good ones. Learn all about gene editing at HowStuffWorks.
Gene therapy is easy to describe on paper but much trickier to implement in human cells. Still, there are success stories. And 'bubble boy' disease, aka severe combined immunodeficiency syndrome, is one of them.