DNA Tests Don’t Consider Environmental Factors
This is a major issue with many DNA tests as they only look at the genetic markers themselves and don’t consider the environmental impact of the DNA.
Many people aren’t familiar with how our DNA works, but essentially is consists of chemically bonded amino acids. Through interactions with the environment and other chemicals within the environment, the bonds between these compounds can be modified and changed, essentially altering the DNA.
To give you an example, one environmental factor that has a huge impact on our DNA is sun exposure. Sunlight contains various forms of radiation, and too much exposure can damage the DNA and even lead to serious issues like skin cancers.
Just finding out that you predisposed to a disease is like receiving only a part of the information needed to determine whether or not you are going to get a disease. A person might be at a higher risk of something but may never develop the condition based on the environment.
Also conversely a person may not have the genetic markers for a certain illness, however their environment may cause or increase the chance of developing the disease anyway.