Genetic engineering is seen as the ultimate answer to treat incurable diseases. Many researchers considered that analyzing abnormal genes, genetic mutations, or even engineering gene knockouts was just the beginning to assess how our genomes are regulated and function. However, learning how to read the genetic code does not give us the answer or ability to correct errors per se. Modifying the human genome has its obvious ethical issues and it has not been considered a safe solution until now. Scientists tried different approaches to safely correct the human genome using diverse techniques such as e.g. retroviral vectors, lentiviral vectors, adeno-associated virus, Chimeric Antigen Receptor (CAR) T cells, and morpholinos. But really modifying the genome is a completely different realm that became more auspicious with the possibility of gene editing techniques such as RNA interference (RNAi). RNAi has an immense potential to genetically down-regulate gene expression and recent results brought new hope to treat patients with Duchenne Muscular Dystrophy (DMD) and Spinal Muscular Atrophy (SMA). However, a solution to rectify or change the genome of a patient with cancer, a rare genetic disease, or even immunological changes caused by HIV/AIDS brings a completely different level of complexity and inherent danger.