Frontiers of Science
With the advent of genetic testing, companies made it available for public services - like InsideTracker. For now there is no discount avialable, I just recommend a great and insightful service.
InsideTracker offers many different plans for specific endpoints. All offer insides into your own body and show how genes are effecting your health, metabolism and reaction to certain external substances and inputs. While knowing of some is more of a fun fact, others can be very beneficial - for example polymorphisms of your MTHFR gene that affect how it works and consequently how your body approaches Methylation. This could have hard impacts and your body could be of an elevated need for Riboflavin instead of Methylfolate, or choline/betaine and carnosine could make a difference for you.
That said, it is one example how a skilled mind can interpret such genetic findings and tailor them to practical approaches regarding nutrition and lifestyle choices.
Understanding Mechanisms
Genetic testing is another powerful tool, likewise a blood draw utilized by medical professionals around the world is. If you know what you're looking for, it can offer valuable insides.
While Genetic testing underwent some harsh critic in regard to designing humans or having too deep a look at what your parents did while creating you, might reap some trauma for some people, but these are individual concerns, not a flaw of the system. In total, I find genetic testing to be a powerful tool and access to the public is a great thing that many other countries, like my home country Germany, should make available.
My Experience
I've never thought about genetic testing, plus Germany manages to attach a propagandistic negatively image to it pretty well. Nonetheless, I stumbled across it while my time in Canada while I dove deep into the MTHFR enzyme, methylation and polymorphisms.
That ultimately made me purchase a test to have a deeper look into my body regarding these underlying mechanisms. And I found a polymorphism that eventually led me to eating more Riboflavin and choline to help my MTHFR sustain its activity. I was a fan by then!
Further Reading
Chris Masterjohn offers a superb Choline calculator that takes the data of your genetic testing and determines how much choline you need a day based on the workings of your body's enzymes. Plus, on his blog he offers a lot of education regarding methylation, genetic testing and potential shortcomings.