As others have observed it is now possible to 'print' a virus using a DNA printer. Further there is growing evidence that viruses are a change agent for evolution as they physically re-write the genetics of a cell to propagate, and even after the virus is conquered sometimes their structure lives on.
When you combine those, you can see that we're approaching a point where a non-nation state actor (basically a smart biologist in reasonably well funded lab) will be able to code a genetic change, print up a retrovirus to make that change, and then instantiate that change in a test subject (or themselves).
Evidence suggests the first 'customers' for that technology will be athletes who are looking for an 'edge' but when it happens, it will appear to have happened 'over night' where something fundamental about a person can be proactively changed. Whether its baldness, red blood cell production, or the color of your eyes, the changes will be profound and for many quite upsetting.
The key is that people will be able to get changed without the regulating agencies being able to intervene and that will change things quite dramatically.
Retro-viri do this. (Not all viri are retro-viri.)