That is a very difficult question to answer....especially for someone that was merely a Biology major.
However, what is clear is that GMO food can lead to infertility (one of the goals of the manufacturers) and so many diseases that it would be difficult to list them all.
Besides diseases and infertility, there are also the abundant birth defects that occur.
...besides the diseases, infertility (the goal of the manufacturers), and birth defects, there is the issue of the poison herbicides and pesticides that the criminals in Monsanto and the United States Food and Drug Administration claim to be "safe."
The nation of France, one of our long time allies, I might add - has recently CONVICTED Monsanto of poisoning it's citizens.
Changes in DNA happen all the time...but over the course of so many years that "all the time" is relative to one's perspective. I'd say it is unlikely at all that GMO foods could change anyone's DNA in one's own lifetime, but regardless, they should all be boycotted, universally banned, and utterly destroyed just the same.