Self-replicating nanobots
The first concern is that of out-of-control, self-replicating "nanobots" that would eventually consume and take over the planet in a style reminiscent to that of "The Matrix".
Alvin Toffler and Heidi Toffler in their brilliant book "War and Anti-War: Making Sense of Today's Global Chaos" theorised the creation of insect-sized attack robots, nano-sized robots which would drill into enemy territory, and start self-replicating to a huge extent. These time-controlled robots could then be set to detonate with the press of a button, providing the ultimate weapon against any army in the world.
Conversely, history shows that if advance technologies, developed by the government have the tendency of falling in the wrong hands, be it animate or inanimate being alike. If terrorists were to perfect or get hold of the technology, it would be akin to planting an atomic bomb in every major city in the world. …