Star Trek: 10 Classified Starfleet Secrets

The development of the Genesis Device started off with good intentions. The device, created by Dr. Carol Marcus, was the most sophisticated terraforming technology in the Federation, but after Khan stole it and detonated it aboard the USS Reliant, the technology's destructive capability was exposed, which made Project Genesis a huge controversy across the quadrant.

All of the science behind the Genesis Device was classified by Starfleet. This, mixed with the drama surrounding Khan, made many neighbours of the Federation, such as the Klingons, very nervous. Ultimately, these fears died down because the tech was soon found to be unstable and the project was scrapped.

So, although almost everyone in the quadrant had heard about the Genesis Device in the 23rd century, the actual science behind it was known to only a few individuals. It's likely that either Starfleet or Section 31 still keep records of the tech, and many other alien species have probably tried to recreate it, but we have so far never seen this on screen.