Short answer: yes, there is.
Long answer: depends on what it is. Some things require very specialized parts and other advancements before they can be created. For example, it's beyond reason that you would invent a cell phone before electricity, or landlines, or cell towers. Plus, a host of other things. A lot of other things necessarily have to come first for many inventions.
The examples already on the answers here are useful--the Baghdad battery, inventions that were brilliant but considered just a nifty magic trick or a toy with no practical application.
But, with your specific story example, you're looking at something that was developed and then kept secret. That it is genetic in nature makes it easier, because anything that's been invented that's been useful gets seen, and if it's seen, people tend to copy it. (Hey, here's a fun Cracked article for your viewing pleasure).
Unless your GMHs (Genetically Modified Humans) look completely different from other people, it's certainly possible for them to exist without anyone knowing. There will be failures first, and they will need to be kept locked down in the lab. Here's what they need:
An area not governed by any government or isolated enough to be kept secret and be legal. It must be stable though. This is important. There can't be revolutions happening every few years.
A way to get and or manufacture supplies without calling attention to what they are doing. Maybe have a mundane reason, and some advancements coming out of the lab ready to feed to curious reporters. If there are any investigative journalists left in the world.
Very good security.
Utterly loyal and amoral employees Treat all employees with respect and pay them so very much money. Let them know how much you like them. Get personal--know their names, and their kid's names, what grades they are in, that kind of thing. Anyone who becomes disloyal will be punished in some terrible way. Perhaps killed. The idea is that those who are good to you will always be taken care of and rewarded, but those that are not...well...that would not be a good idea.
A Reason for the Secrecy Hide, not quite in plain sight, make sure there's an alt cover story, like something slightly illegal or amoral, but not enough to get you hauled to international courts, which you can then "confess" when someone gets too close. Then, close the place and use one of your OTHER super-secret labs.
Maybe don't let your experiments roam free Just a tip.
This is fiction, so it's certainly possible. Just keep in mind that the first generation of anything is buggy as heck and that these other inventions simply aren't the same as genetic modification. Also keep in mind that if it's on the edge of possible and it's useful, someone is pouring money into it--so they won't be the only ones.
Now, one way to go with this is ONE DISCOVERY THAT CHANGES EVERYTHING. Like something upon which all the advancements are based that nobody else has. Here's a fictional video game example: Bioshock. The genetic modifications everyone in Rapture can experience through gene splicing are all the result of discovering a deep sea slug, with properties that change gene stability. In order for your guys to have some advancement beyond everyone else, I believe that they would have to have a game changer in their corner.
But it does mean that anything they make public MUST absolutely be free of evidence of the game changer. They can call it proprietary. If it touches on impossible, people will try to reverse engineer it.